Signed-off-by: Ola Liljedahl <[email protected]>
---
(This document/code contribution attached is provided under the terms of
agreement LES-LTM-21309)
The timer API is updated according to 
https://docs.google.com/a/linaro.org/document/d/1bfY_J8ecLJPsFTmYftb0NVmGnB9qkEc_NpcJ87yfaD8
A major change is that timers are allocated and freed separately from timeouts
being set and cancelled. The life-length of a timer normally corresponds to the
life-length of the associated stateful flow while the life-length of a timeout
corresponds to individual packets being transmitted and received.
The reference timer implementation is lock-less for platforms with support
for 128-bit (16-byte) atomic exchange and CAS operations. Otherwise a lock-based
implementation (using as many locks as desired) is used but some operations
(e.g. reset re-using existing timeout buffer) may still be lock-less.
Updated the example example/timer/odp_timer_test.c.

 example/timer/odp_timer_test.c                     |  165 ++-
 platform/linux-generic/include/api/odp_timer.h     |  474 +++++++--
 .../linux-generic/include/odp_timer_internal.h     |   69 +-
 platform/linux-generic/odp_timer.c                 | 1083 ++++++++++++++------
 4 files changed, 1311 insertions(+), 480 deletions(-)

diff --git a/example/timer/odp_timer_test.c b/example/timer/odp_timer_test.c
index 9968bfe..b71e3f1 100644
--- a/example/timer/odp_timer_test.c
+++ b/example/timer/odp_timer_test.c
@@ -43,67 +43,116 @@ typedef struct {
 /** @private Barrier for test synchronisation */
 static odp_barrier_t test_barrier;
 
-/** @private Timer handle*/
-static odp_timer_t test_timer;
+/** @private Buffer pool handle */
+static odp_buffer_pool_t pool;
 
+/** @private Timer pool handle */
+static odp_timer_pool_t tp;
+
+/** @private Timeout status ASCII strings */
+static const char *const status2str[] = {
+       "fresh", "stale", "orphaned"
+};
+
+/** @private Timer set status ASCII strings */
+static const char *timerset2str(uint64_t val)
+{
+       switch (val) {
+       case ODP_TICK_TOOEARLY:
+               return "tooearly";
+       case ODP_TICK_TOOLATE:
+               return "toolate";
+       case ODP_TICK_INVALID:
+               return "error";
+       default:
+               return "success";
+       }
+};
+
+/** @private Helper struct for timers */
+struct test_timer {
+       odp_timer_t tim;
+       odp_buffer_t buf;
+       uint64_t tick;
+};
+
+/** @private Array of all timer helper structs */
+static struct test_timer tt[256];
 
 /** @private test timeout */
 static void test_abs_timeouts(int thr, test_args_t *args)
 {
-       uint64_t tick;
        uint64_t period;
        uint64_t period_ns;
        odp_queue_t queue;
-       odp_buffer_t buf;
-       int num;
+       int remain = args->tmo_count;
+       uint64_t tick;
+       struct test_timer *ttp;
 
        EXAMPLE_DBG("  [%i] test_timeouts\n", thr);
 
        queue = odp_queue_lookup("timer_queue");
 
        period_ns = args->period_us*ODP_TIME_USEC;
-       period    = odp_timer_ns_to_tick(test_timer, period_ns);
+       period    = odp_timer_ns_to_tick(tp, period_ns);
 
        EXAMPLE_DBG("  [%i] period %"PRIu64" ticks,  %"PRIu64" ns\n", thr,
                    period, period_ns);
 
-       tick = odp_timer_current_tick(test_timer);
+       EXAMPLE_DBG("  [%i] current tick %"PRIu64"\n", thr,
+                   odp_timer_current_tick(tp));
 
-       EXAMPLE_DBG("  [%i] current tick %"PRIu64"\n", thr, tick);
-
-       tick += period;
-
-       if (odp_timer_absolute_tmo(test_timer, tick, queue, ODP_BUFFER_INVALID)
-           == ODP_TIMER_TMO_INVALID){
-               EXAMPLE_DBG("Timeout request failed\n");
+       ttp = &tt[thr - 1]; /* Thread starts at 1 */
+       ttp->tim = odp_timer_alloc(tp, queue, ttp);
+       if (ttp->tim == ODP_TIMER_INVALID) {
+               EXAMPLE_ERR("Failed to allocate timer\n");
                return;
        }
+       ttp->buf = odp_buffer_alloc(pool);
+       if (ttp->buf == ODP_BUFFER_INVALID) {
+               EXAMPLE_ERR("Failed to allocate buffer\n");
+               return;
+       }
+       tick = odp_timer_current_tick(tp);
 
-       num = args->tmo_count;
-
-       while (1) {
-               odp_timeout_t tmo;
-
-               buf = odp_schedule_one(&queue, ODP_SCHED_WAIT);
-
-               tmo  = odp_timeout_from_buffer(buf);
-               tick = odp_timeout_tick(tmo);
-
-               EXAMPLE_DBG("  [%i] timeout, tick %"PRIu64"\n", thr, tick);
-
-               odp_buffer_free(buf);
-
-               num--;
-
-               if (num == 0)
-                       break;
+       while (remain != 0) {
+               odp_buffer_t buf;
 
                tick += period;
+               ttp->tick = odp_timer_set_abs(ttp->tim, tick, &ttp->buf);
+               if (odp_unlikely(ttp->tick == ODP_TICK_TOOEARLY ||
+                                ttp->tick == ODP_TICK_TOOLATE ||
+                                ttp->tick == ODP_TICK_INVALID)) {
+                       /* Too early or too late timeout requested */
+                       EXAMPLE_ABORT("odp_timer_set_abs() failed: %s\n",
+                                     timerset2str(ttp->tick));
+               }
 
-               odp_timer_absolute_tmo(test_timer, tick,
-                                      queue, ODP_BUFFER_INVALID);
+               /* Get the next expired timeout */
+               buf = odp_schedule_one(&queue, ODP_SCHED_WAIT);
+               if (odp_timer_tmo_metadata(buf, NULL, &tick, (void **)&ttp)) {
+                       ttp->buf = buf;
+                       if (odp_likely(tick != ttp->tick)) {
+                               /* Not the expected expiration tick, timer has
+                                * been reset or cancelled or freed */
+                               EXAMPLE_ABORT("Unexpected timeout received 
(timer %x, tick %"PRIu64", expected %"PRIu64")\n",
+                                             ttp->tim, tick, ttp->tick);
+                       }
+                       EXAMPLE_DBG("  [%i] timeout, tick %"PRIu64"\n",
+                                   thr, tick);
+                       remain--;
+               } else {
+                       /* Not a default timeout buffer */
+                       EXAMPLE_ABORT("Unexpected buffer type (%u) received\n",
+                                     odp_buffer_type(buf));
+               }
        }
 
+       /* Free last timer used */
+       ttp->tick = odp_timer_free(ttp->tim, &ttp->buf);
+       if (ttp->buf != ODP_BUFFER_INVALID)
+               odp_buffer_free(ttp->buf);
+
        if (odp_queue_sched_type(queue) == ODP_SCHED_SYNC_ATOMIC)
                odp_schedule_release_atomic();
 }
@@ -192,14 +241,14 @@ static void parse_args(int argc, char *argv[], 
test_args_t *args)
        /* defaults */
        args->core_count    = 0; /* all cores */
        args->resolution_us = 10000;
-       args->min_us        = args->resolution_us;
+       args->min_us        = 0;
        args->max_us        = 10000000;
        args->period_us     = 1000000;
        args->tmo_count     = 30;
 
        while (1) {
                opt = getopt_long(argc, argv, "+c:r:m:x:p:t:h",
-                                longopts, &long_index);
+                                 longopts, &long_index);
 
                if (opt == -1)
                        break;  /* No more options */
@@ -243,13 +292,13 @@ int main(int argc, char *argv[])
        odph_linux_pthread_t thread_tbl[MAX_WORKERS];
        test_args_t args;
        int num_workers;
-       odp_buffer_pool_t pool;
        void *pool_base;
        odp_queue_t queue;
        int first_core;
        uint64_t cycles, ns;
        odp_queue_param_t param;
        odp_shm_t shm;
+       odp_timer_pool_info_t tpinfo;
 
        printf("\nODP timer example starts\n");
 
@@ -309,7 +358,7 @@ int main(int argc, char *argv[])
        printf("timeouts:           %i\n", args.tmo_count);
 
        /*
-        * Create message pool
+        * Create buffer pool for timeouts
         */
        shm = odp_shm_reserve("msg_pool",
                              MSG_POOL_SIZE, ODP_CACHE_LINE_SIZE, 0);
@@ -321,9 +370,32 @@ int main(int argc, char *argv[])
                                      ODP_BUFFER_TYPE_TIMEOUT);
 
        if (pool == ODP_BUFFER_POOL_INVALID) {
-               EXAMPLE_ERR("Pool create failed.\n");
+               EXAMPLE_ERR("Buffer pool create failed.\n");
+               return -1;
+       }
+
+       tp = odp_timer_pool_create("timer_pool", pool,
+                                  args.resolution_us*ODP_TIME_USEC,
+                                  args.min_us*ODP_TIME_USEC,
+                                  args.max_us*ODP_TIME_USEC,
+                                  num_workers, /* One timer per worker */
+                                  true,
+                                  ODP_CLOCK_CPU);
+       if (tp == ODP_TIMER_POOL_INVALID) {
+               EXAMPLE_ERR("Timer pool create failed.\n");
                return -1;
        }
+       odp_timer_pool_start();
+
+       odp_shm_print_all();
+       (void)odp_timer_pool_info(tp, &tpinfo, sizeof(tpinfo));
+       printf("Timer pool\n");
+       printf("----------\n");
+       printf("  name: %s\n", tpinfo.name);
+       printf("  resolution: %"PRIu64" ns\n", tpinfo.resolution);
+       printf("  min tmo: %"PRIu64" ticks\n", tpinfo.min_tmo);
+       printf("  max tmo: %"PRIu64" ticks\n", tpinfo.max_tmo);
+       printf("\n");
 
        /*
         * Create a queue for timer test
@@ -340,20 +412,7 @@ int main(int argc, char *argv[])
                return -1;
        }
 
-       test_timer = odp_timer_create("test_timer", pool,
-                                     args.resolution_us*ODP_TIME_USEC,
-                                     args.min_us*ODP_TIME_USEC,
-                                     args.max_us*ODP_TIME_USEC);
-
-       if (test_timer == ODP_TIMER_INVALID) {
-               EXAMPLE_ERR("Timer create failed.\n");
-               return -1;
-       }
-
-
-       odp_shm_print_all();
-
-       printf("CPU freq %"PRIu64" hz\n", odp_sys_cpu_hz());
+       printf("CPU freq %"PRIu64" Hz\n", odp_sys_cpu_hz());
        printf("Cycles vs nanoseconds:\n");
        ns = 0;
        cycles = odp_time_ns_to_cycles(ns);
diff --git a/platform/linux-generic/include/api/odp_timer.h 
b/platform/linux-generic/include/api/odp_timer.h
index 6cca27c..f8ecf64 100644
--- a/platform/linux-generic/include/api/odp_timer.h
+++ b/platform/linux-generic/include/api/odp_timer.h
@@ -8,9 +8,211 @@
 /**
  * @file
  *
- * ODP timer
+ * ODP timer service
  */
 
+/** Example #1 Retransmission timer (e.g. for reliable connections)
+ @code
+
+//Create timer pool for reliable connections
+#define SEC 1000000000ULL //1s expressed in nanoseconds
+odp_timer_pool_t tcp_tpid =
+    odp_timer_pool_create("TCP",
+                         buffer_pool,
+                         1000000,//resolution 1ms
+                         0,//min tmo
+                         7200 * SEC,//max tmo length 2hours
+                         40000,//num_timers
+                         true,//shared
+                         ODP_CLOCK_CPU
+                        );
+if (tcp_tpid == ODP_TIMER_POOL_INVALID)
+{
+       //Failed to create timer pool => fatal error
+}
+
+
+//Setting up a new connection
+//Allocate retransmission timeout (identical for supervision timeout)
+//The user pointer points back to the connection context
+conn->ret_tim = odp_timer_alloc(tcp_tpid, queue, conn);
+//Check if all resources were successfully allocated
+if (conn->ret_tim == ODP_TIMER_INVALID)
+{
+       //Failed to allocate all resources for connection => tear down
+       //Tear down connection
+       ...
+       return false;
+}
+//All necessary resources successfully allocated
+//Compute initial retransmission length in timer ticks
+conn->ret_len = odp_timer_ns_to_tick(tcp_tpid, 3 * SEC);//Per RFC1122
+//Allocate a timeout buffer
+conn->tmo_buf = odp_buffer_alloc(buffer_pool);
+if (conn->tmo_buf == ODP_BUFFER_INVALID)
+       ODP_ABORT("Failed to allocate timeout buffer\n");
+//Arm the timer with our timeout
+conn->expected = odp_timer_set_rel(conn->ret_tim, conn->ret_len,
+                                  &conn->tmo_buf);
+//Check return value for too early or too late expiration tick
+return true;
+
+
+//A packet for the connection has just been transmitted
+//Reset the retransmission timer, reusing the previously specified timeout
+conn->expected = odp_timer_set_rel(conn->ret_tim, conn->ret_len, NULL);
+if (conn->expected == ODP_TICK_INVALID) {
+       //Timer has expired
+       //We could allocate another timeout buffer and reset the timer with it
+       ...
+}
+//Else check return value for too early or too late expiration tick
+
+
+//Check if the buffer is a system timeout buffer
+if (!odp_timer_tmo_metadata(&buf, NULL, &exp_tick, (void**)&conn)) {
+       //Not a system timeout buffer
+       ...
+}
+//A retransmission timeout buffer for the connection has been received
+conn->tmo_buf = buf;
+//Check if timeout is fresh or stale, for stale timeouts we need to reset the
+//timer
+if (conn->expected == exp_tick) {
+       //Fresh timeout, last transmitted packet not acked in time =>
+         retransmit
+       //Retransmit last packet (e.g. TCP segment)
+       ...
+       //Re-arm timer using original delta value
+       odp_timer_set_rel(conn->ret_tim, conn->ret_len, &conn->tmo_buf);
+} else {
+       //Timeout does not have the expected expiration tick, timer has been
+       //reset or cancelled
+       //We can ignore the timeout or reset the timer to the expected tick
+       if (conn->expected != ODP_TICK_INVALID)
+               (void)odp_timer_set_abs(conn->ret_tim, conn->expected,
+                                       &conn->tmo_buf);
+}
+
+ @endcode
+*/
+
+/** Example #2 Periodic tick
+ @code
+
+//Create timer pool for periodic ticks
+odp_timer_pool_t per_tpid =
+    odp_timer_pool_create("periodic-tick",
+                         buffer_pool,
+                         1,//resolution 1ns
+                         1,//minimum timeout length 1ns
+                         1000000000,//maximum timeout length 1s
+                         10,//num_timers
+                         false,//not shared
+                         ODP_CLOCK_CPU
+                        );
+if (per_tpid == ODP_TIMER_POOL_INVALID)
+{
+       //Failed to create timer pool => fatal error
+}
+
+
+//Allocate periodic timer
+tim_1733 = odp_timer_alloc(per_tpid, queue, NULL);
+//Check if all resources were successfully allocated
+if (tim_1733 == ODP_TIMER_INVALID)
+{
+       //Failed to allocate all resources => tear down
+       //Tear down other state
+       ...
+       return false;
+}
+//All necessary resources successfully allocated
+//Compute tick period in timer ticks
+period_1733 = odp_timer_ns_to_tick(per_tpid, 1000000000U / 1733U);//1733Hz
+//Compute when next tick should expire
+next_1733 = odp_timer_current_tick(per_tpid) + period_1733;
+//Allocate a timeout buffer
+buf_1733 = odp_buffer_alloc(buffer_pool);
+if (buf_1733 == ODP_BUFFER_INVALID)
+       ODP_ABORT("Failed to allocate timeout buffer\n");
+//Arm the periodic timer
+(void)odp_timer_set_abs(tim_1733, next_1733, &buf_1733);
+return true;
+
+
+
+//Check if the buffer is a system timeout buffer
+if (!odp_timer_tmo_metadata(&buf, &timer, NULL, NULL)) {
+       //Not a system timeout buffer
+       ...
+}
+if (timer != tim_1733) {
+       //Not our periodic timer
+       ...
+}
+//A periodic timer timeout has been received
+//Do processing driven by timeout *before*
+...
+do {
+       //Compute when the timer should expire next
+       next_1733 += period_1733;
+       //Check that this is in the future
+       if (likely(next_1733 > odp_timer_current_tick(per_tpid))
+               break;//Yes, done
+       //Else we missed a timeout
+       //Optionally attempt some recovery and/or logging of the problem
+       ...
+} while (1);
+//Re-arm periodic timer
+(void)odp_timer_set_abs(tim_1733, next_1733, &buf);
+//Or do processing driven by timeout *after*
+...
+return;
+
+ @endcode
+*/
+
+/** Example #3 Tear down of flow
+ @code
+//ctx points to flow context data structure owned by application
+//Free the timer, cancelling any timeout
+ctx->expected = odp_timer_free(ctx->timer, &ctx->tmo_buf);
+//Invalidate our save timer handle
+ctx->timer = ODP_TIMER_INVALID;
+if (ctx->tmo_buf != ODP_BUFFER_INVALID) {
+       //Tear down the flow
+       ...
+       odp_buffer_free(ctx->tmo_buf);
+       //Free flow context
+       ..
+       //Teardown complete
+} else {
+       //Timer had already expired and timeout enqueued
+       //Continue teardown when receiving timeout
+       ctx->teardown_in_progress = true;
+}
+return;
+
+//A buffer has been received, check type
+if (!odp_timer_tmo_metadata(buf, &timer, NULL, (void**)&ctx)) {
+       //Not a system timeout buffer
+       ...
+}
+ctx->tmo_buf = buf;
+//Check if we are tearing down flow
+if (ctx->teardown_in_progress) {
+       //Continue tearing down the flow
+       //Free the timeout buffer
+       odp_buffer_free(ctx->tmo_buf));
+       //Free the context
+       ...
+       //Teardown complete
+}
+
+ @endcode
+*/
+
 #ifndef ODP_TIMER_H_
 #define ODP_TIMER_H_
 
@@ -18,6 +220,7 @@
 extern "C" {
 #endif
 
+#include <stdlib.h>
 #include <odp_std_types.h>
 #include <odp_buffer.h>
 #include <odp_buffer_pool.h>
@@ -27,138 +230,283 @@ extern "C" {
  *  @{
  */
 
-/**
- * ODP timer handle
- */
-typedef uint32_t odp_timer_t;
-
-/** Invalid timer */
-#define ODP_TIMER_INVALID 0
+struct odp_timer_pool_s; /**< Forward declaration */
 
+/**
+* ODP timer pool handle (platform dependent)
+*/
+typedef struct odp_timer_pool_s *odp_timer_pool_t;
 
 /**
- * ODP timeout handle
+ * Invalid timer pool handle (platform dependent).
  */
-typedef odp_buffer_t odp_timer_tmo_t;
+#define ODP_TIMER_POOL_INVALID NULL
 
-/** Invalid timeout */
-#define ODP_TIMER_TMO_INVALID 0
+/**
+ * Clock sources for timers in timer pool.
+ */
+typedef enum odp_timer_clk_src_e {
+       /** Use CPU clock as clock source for timers */
+       ODP_CLOCK_CPU,
+       /** Use external clock as clock source for timers */
+       ODP_CLOCK_EXT
+       /* Platform dependent which other clock sources exist */
+} odp_timer_clk_src_t;
 
+/**
+* ODP timer handle (platform dependent).
+*/
+typedef uint32_t odp_timer_t;
 
 /**
- * Timeout notification
+ * Invalid timer handle (platform dependent).
  */
-typedef odp_buffer_t odp_timeout_t;
+#define ODP_TIMER_INVALID ((uint32_t)~0U)
 
+/**
+ * Return values of timer set calls.
+ */
+/**
+ * Timer set operation failed, expiration too early.
+ * Either retry with a later expiration time or process the timeout
+ * immediately. */
+#define ODP_TICK_TOOEARLY 0xFFFFFFFFFFFFFFFDULL
+/**
+ * Timer set operation failed, expiration too late.
+ * Truncate the expiration time against the maximum timeout for the
+ * timer pool. */
+#define ODP_TICK_TOOLATE  0xFFFFFFFFFFFFFFFEULL
+/**
+ * Timer set operation failed because not timeout buffer present or specified.
+ * This value is also return from odp_timer_cancel() and odp_timer_free().
+ */
+#define ODP_TICK_INVALID  0xFFFFFFFFFFFFFFFFULL
 
 /**
- * Create a timer
+ * Create a timer pool
  *
- * Creates a new timer with requested properties.
+ * Create a new timer pool.
  *
  * @param name       Name
- * @param pool       Buffer pool for allocating timeout notifications
+ * @param buf_pool   Buffer pool for allocating timeouts (and only timeouts)
  * @param resolution Timeout resolution in nanoseconds
- * @param min_tmo    Minimum timeout duration in nanoseconds
- * @param max_tmo    Maximum timeout duration in nanoseconds
+ * @param min_tmo    Minimum relative timeout in nanoseconds
+ * @param max_tmo    Maximum relative timeout in nanoseconds
+ * @param num_timers Number of supported timers (minimum)
+ * @param shared     Shared or private timer pool.
+ *                Operations on shared timers will include the necessary
+ *                mutual exclusion, operations on private timers may not
+ *                (mutual exclusion is the responsibility of the caller).
+ * @param clk_src    Clock source to use
+ *
+ * @return Timer pool handle if successful, otherwise ODP_TIMER_POOL_INVALID
+ * and errno set
+ */
+odp_timer_pool_t
+odp_timer_pool_create(const char *name,
+                     odp_buffer_pool_t buf_pool,
+                     uint64_t resolution,
+                     uint64_t min_tmo,
+                     uint64_t max_tmo,
+                     uint32_t num_timers,
+                     int shared,
+                     odp_timer_clk_src_t clk_src);
+
+/**
+ * Start a timer pool
+ *
+ * Start all created timer pools, enabling the allocation of timers.
+ * The purpose of this call is to coordinate the creation of multiple timer
+ * pools that may use the same underlying HW resources.
+ * This function may be called multiple times.
+ */
+void odp_timer_pool_start(void);
+
+/**
+ * Destroy a timer pool
  *
- * @return Timer handle if successful, otherwise ODP_TIMER_INVALID
+ * Destroy a timer pool, freeing all resources.
+ * All timers must have been freed.
+ *
+ * @param tpid  Timer pool identifier
  */
-odp_timer_t odp_timer_create(const char *name, odp_buffer_pool_t pool,
-                            uint64_t resolution, uint64_t min_tmo,
-                            uint64_t max_tmo);
+void odp_timer_pool_destroy(odp_timer_pool_t tpid);
 
 /**
  * Convert timer ticks to nanoseconds
  *
- * @param timer Timer
+ * @param tpid  Timer pool identifier
  * @param ticks Timer ticks
  *
  * @return Nanoseconds
  */
-uint64_t odp_timer_tick_to_ns(odp_timer_t timer, uint64_t ticks);
+uint64_t odp_timer_tick_to_ns(odp_timer_pool_t tpid, uint64_t ticks);
 
 /**
  * Convert nanoseconds to timer ticks
  *
- * @param timer Timer
+ * @param tpid  Timer pool identifier
  * @param ns    Nanoseconds
  *
  * @return Timer ticks
  */
-uint64_t odp_timer_ns_to_tick(odp_timer_t timer, uint64_t ns);
+uint64_t odp_timer_ns_to_tick(odp_timer_pool_t tpid, uint64_t ns);
 
 /**
- * Timer resolution in nanoseconds
+ * Current tick value
  *
- * @param timer Timer
+ * @param tpid Timer pool identifier
  *
- * @return Resolution in nanoseconds
+ * @return Current time in timer ticks
  */
-uint64_t odp_timer_resolution(odp_timer_t timer);
+uint64_t odp_timer_current_tick(odp_timer_pool_t tpid);
 
 /**
- * Maximum timeout in timer ticks
+ * ODP timer pool information and configuration
+ */
+
+typedef struct odp_timer_pool_info_s {
+       uint64_t resolution;/**< Timer resolution (in ns) */
+       uint64_t min_tmo;   /**< Min supported relative timeout (in ticks)*/
+       uint64_t max_tmo;   /**< Max supported relative timeout (in ticks)*/
+       uint32_t num_timers;/**< Number of supported timers */
+       uint32_t cur_timers;/**< Number of currently allocated timers */
+       uint32_t hwm_timers;/**< Number of used timers high watermark */
+       int shared;         /**< Shared flag */
+       char name[80];      /**< Name of timer pool */
+} odp_timer_pool_info_t;
+
+/**
+ * Query timer pool information and configuration
+ *  Timer resolution in nanoseconds
+ *  Minimum and maximum (relative) timeouts in timer ticks
+ *  Number of supported timers
+ *  Nunber of timers in use
+ *  Nunber of timers in use - high watermark
+ *  Shared or private timer pool
+ *  Name of timer pool.
  *
- * @param timer Timer
+ * @param tpid Timer pool identifier
+ * @param buf Pointer to information buffer
+ * @param buf_size Size of information buffer
  *
- * @return Maximum timeout in timer ticks
+ * @return Actual size written
  */
-uint64_t odp_timer_maximum_tmo(odp_timer_t timer);
+size_t odp_timer_pool_info(odp_timer_pool_t tpid,
+                          odp_timer_pool_info_t *buf,
+                          size_t buf_size);
 
 /**
- * Current timer tick
+ * Allocate a timer
  *
- * @param timer Timer
+ * Create a timer (allocating all necessary resources e.g. timeout event) from
+ * the timer pool. The user_ptr is copied to timeouts and can be retrieved
+ * using the odp_timer_userptr() call.
  *
- * @return Current time in timer ticks
+ * @param tpid     Timer pool identifier
+ * @param queue    Destination queue for timeout notifications
+ * @param user_ptr User defined pointer or NULL to be copied to timeouts
+ *
+ * @return Timer handle if successful, otherwise ODP_TIMER_INVALID and
+ *        errno set.
+ */
+odp_timer_t odp_timer_alloc(odp_timer_pool_t tpid,
+                           odp_queue_t queue,
+                           void *user_ptr);
+
+/**
+ * Free a timer
+ *
+ * Free (destroy) a timer, freeing associated resources.
+ * The timeout buffer for an active timer will be returned.
+ * An expired and enqueued timeout buffer will not be freed.
+ * It is the responsibility of the application to free this timeout when it
+ * is received.
+ *
+ * @param tim      Timer handle
+ * @param tmo_buf Reference to a buffer variable which will be written with
+ * the buffer handle of any present timeout buffer (e.g. for an active timer).
+ * @return       A tick value which will not match any valid expiration tick.
  */
-uint64_t odp_timer_current_tick(odp_timer_t timer);
+uint64_t odp_timer_free(odp_timer_t tim, odp_buffer_t *tmo_buf);
 
 /**
- * Request timeout with an absolute timer tick
+ * Set a timer (absolute time) with a user-provided timeout buffer
+ *
+ * Set (arm) the timer to expire at specific time. The timeout
+ * buffer will be enqueued when the timer expires.
  *
- * When tick reaches tmo_tick, the timer enqueues the timeout notification into
- * the destination queue.
+ * Note: any invalid parameters will be treated as programming errors and will
+ * cause the application to abort.
  *
- * @param timer    Timer
- * @param tmo_tick Absolute timer tick value which triggers the timeout
- * @param queue    Destination queue for the timeout notification
- * @param buf      User defined timeout notification buffer. When
- *                 ODP_BUFFER_INVALID, default timeout notification is used.
+ * @param tim      Timer
+ * @param abs_tck  Expiration time in absolute timer ticks
+ * @param tmo_buf  Reference to a buffer variable that points to timeout buffer
+ * or NULL to reuse the existing timeout buffer
  *
- * @return Timeout handle if successful, otherwise ODP_TIMER_TMO_INVALID
+ * @return The expiration tick or ODP_TICK_TOOEARLY, ODP_TICK_TOOLATE or
+ * ODP_TICK_INVALID (timer not active and no timeout buffer to reuse).
  */
-odp_timer_tmo_t odp_timer_absolute_tmo(odp_timer_t timer, uint64_t tmo_tick,
-                                      odp_queue_t queue, odp_buffer_t buf);
+uint64_t odp_timer_set_abs(odp_timer_t tim,
+                          uint64_t abs_tck,
+                          odp_buffer_t *tmo_buf);
 
 /**
- * Cancel a timeout
+ * Set a timer with a relative expiration time and user-provided buffer.
  *
- * @param timer Timer
- * @param tmo   Timeout to cancel
+ * Set (arm) the timer to expire at a relative future time.
  *
- * @return 0 if successful
+ * Note: any invalid parameters will be treated as programming errors and will
+ * cause the application to abort.
+ *
+ * @param tim      Timer
+ * @param rel_tck  Expiration time in timer ticks relative to current time of
+ *                the timer pool the timer belongs to
+ * @param tmo_buf  Reference to a buffer variable that points to timeout buffer
+ * or NULL to reuse the existing timeout buffer
+ *
+ * @return The expiration tick or ODP_TICK_TOOEARLY, ODP_TICK_TOOLATE or
+ * ODP_TICK_INVALID (timer not active and no timeout buffer to reuse).
  */
-int odp_timer_cancel_tmo(odp_timer_t timer, odp_timer_tmo_t tmo);
+uint64_t odp_timer_set_rel(odp_timer_t tim,
+                          uint64_t rel_tck,
+                          odp_buffer_t *tmo_buf);
 
 /**
- * Convert buffer handle to timeout handle
+ * Cancel a timer
+ *
+ * Cancel a timer, preventing future expiration and delivery. Return any
+ * present timeout buffer.
+ *
+ * A timer that has already expired may be impossible to cancel and the timeout
+ * will instead be delivered to the destination queue.
  *
- * @param buf  Buffer handle
+ * Note: any invalid parameters will be treated as programming errors and will
+ * cause the application to abort.
  *
- * @return Timeout buffer handle
+ * @param tim     Timer
+ * @param tmo_buf Reference to a buffer variable which will be written with
+ * the buffer handle of any present timeout buffer (e.g. for an active timer).
+ * @return       A tick value which will not match any valid expiration tick.
  */
-odp_timeout_t odp_timeout_from_buffer(odp_buffer_t buf);
+uint64_t odp_timer_cancel(odp_timer_t tim, odp_buffer_t *tmo_buf);
 
 /**
- * Return absolute timeout tick
+ * Get metadata from system timeout buffer
  *
- * @param tmo Timeout buffer handle
+ * @param buf A timeout buffer
+ * @param hdl NULL or a pointer where the timer handle will be written.
+ * @param exp_tck NULL or a pointer where the expiration tick will be written.
+ * @param user_ptr NULL or a pointer where the user pointer will be written.
  *
- * @return Absolute timeout tick
+ * @return True (1) if timeout buffer is of type ODP_BUFFER_TYPE_TIMEOUT and
+ *         metadata variables have been updated from the timeout.
+ *         False (0) if timeout buffer is not of type ODP_BUFFER_TYPE_TIMEOUT.
  */
-uint64_t odp_timeout_tick(odp_timeout_t tmo);
+int odp_timer_tmo_metadata(odp_buffer_t buf,
+               odp_timer_t *hdl,
+               uint64_t *exp_tck,
+               void **user_ptr);
 
 /**
  * @}
diff --git a/platform/linux-generic/include/odp_timer_internal.h 
b/platform/linux-generic/include/odp_timer_internal.h
index ad28f53..0e0cf48 100644
--- a/platform/linux-generic/include/odp_timer_internal.h
+++ b/platform/linux-generic/include/odp_timer_internal.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2013, Linaro Limited
+/* Copyright (c) 2014, Linaro Limited
  * All rights reserved.
  *
  * SPDX-License-Identifier:     BSD-3-Clause
@@ -8,72 +8,49 @@
 /**
  * @file
  *
- * ODP timer timeout descriptor - implementation internal
+ * ODP timeout descriptor - implementation internal
  */
 
 #ifndef ODP_TIMER_INTERNAL_H_
 #define ODP_TIMER_INTERNAL_H_
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#include <odp_std_types.h>
-#include <odp_queue.h>
-#include <odp_buffer.h>
+#include <odp_align.h>
+#include <odp_debug.h>
 #include <odp_buffer_internal.h>
 #include <odp_buffer_pool_internal.h>
 #include <odp_timer.h>
 
-struct timeout_t;
-
-typedef struct timeout_t {
-       struct timeout_t *next;
-       int               timer_id;
-       int               tick;
-       uint64_t          tmo_tick;
-       odp_queue_t       queue;
-       odp_buffer_t      buf;
-       odp_buffer_t      tmo_buf;
-} timeout_t;
-
-
-struct odp_timeout_hdr_t;
-
 /**
- * Timeout notification header
+ * Internal Timeout header
  */
-typedef struct odp_timeout_hdr_t {
+typedef struct {
+       /* common buffer header */
        odp_buffer_hdr_t buf_hdr;
 
-       timeout_t meta;
-
-       uint8_t buf_data[];
+       /* Requested expiration time */
+       uint64_t expiration;
+       /* User ptr inherited from parent timer */
+       void *user_ptr;
+       /* Parent timer */
+       odp_timer_t timer;
+#if __SIZEOF_POINTER__ != 4
+       uint32_t pad32;
+#endif
+       uint8_t buf_data[0];
 } odp_timeout_hdr_t;
 
-
-
 ODP_STATIC_ASSERT(sizeof(odp_timeout_hdr_t) ==
-          ODP_OFFSETOF(odp_timeout_hdr_t, buf_data),
-          "ODP_TIMEOUT_HDR_T__SIZE_ERR");
-
+                 ODP_OFFSETOF(odp_timeout_hdr_t, buf_data),
+                 "sizeof(odp_timeout_hdr_t) == ODP_OFFSETOF(odp_timeout_hdr_t, 
buf_data)");
 ODP_STATIC_ASSERT(sizeof(odp_timeout_hdr_t) % sizeof(uint64_t) == 0,
-          "ODP_TIMEOUT_HDR_T__SIZE_ERR2");
-
+                 "sizeof(odp_timeout_hdr_t) % sizeof(uint64_t) == 0");
 
 /**
- * Return timeout header
+ * Return the timeout header
  */
-static inline odp_timeout_hdr_t *odp_timeout_hdr(odp_timeout_t tmo)
+static inline odp_timeout_hdr_t *odp_timeout_hdr(odp_buffer_t buf)
 {
-       odp_buffer_hdr_t *buf_hdr = odp_buf_to_hdr((odp_buffer_t)tmo);
-       return (odp_timeout_hdr_t *)(uintptr_t)buf_hdr;
-}
-
-
-
-#ifdef __cplusplus
+       return (odp_timeout_hdr_t *)odp_buf_to_hdr(buf);
 }
-#endif
 
 #endif
diff --git a/platform/linux-generic/odp_timer.c 
b/platform/linux-generic/odp_timer.c
index a4fef58..02a460b 100644
--- a/platform/linux-generic/odp_timer.c
+++ b/platform/linux-generic/odp_timer.c
@@ -4,428 +4,875 @@
  * SPDX-License-Identifier:     BSD-3-Clause
  */
 
-#include <odp_timer.h>
-#include <odp_timer_internal.h>
-#include <odp_time.h>
-#include <odp_buffer_pool_internal.h>
-#include <odp_internal.h>
+/**
+ * @file
+ *
+ * ODP timer service
+ *
+ */
+
+/* Check if compiler supports 16-byte atomics. GCC needs -mcx16 flag */
+/* Using spin lock actually seems faster on Core2 */
+#ifdef ODP_ATOMIC_U128
+/* TB_NEEDS_PAD defined if sizeof(odp_buffer_t) != 8 */
+#define TB_NEEDS_PAD
+#define TB_SET_PAD(x) ((x).pad = 0)
+#else
+#define TB_SET_PAD(x) (void)(x)
+#endif
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+#include <signal.h>
 #include <odp_atomic.h>
+#include <odp_atomic_internal.h>
+#include <odp_std_types.h>
+#include <odp_buffer.h>
+#include <odp_buffer_pool.h>
+#include <odp_queue.h>
+#include <odp_hints.h>
 #include <odp_spinlock.h>
 #include <odp_sync.h>
 #include <odp_debug_internal.h>
+#include <odp_debug.h>
+#include <odp_align.h>
+#include <odp_align_internal.h>
+#include <odp_shared_memory.h>
+#include <odp_hints.h>
+#include <odp_internal.h>
+#include <odp_time.h>
+#include <odp_timer.h>
+#include <odp_timer_internal.h>
 
-#include <signal.h>
-#include <time.h>
+#define TMO_UNUSED   ((uint64_t)0xFFFFFFFFFFFFFFFF)
+#define TMO_INACTIVE ((uint64_t)0xFFFFFFFFFFFFFFFE)
 
-#include <string.h>
+#ifdef __ARM_ARCH
+#define PREFETCH(ptr) __builtin_prefetch((ptr), 0, 0)
+#else
+#define PREFETCH(ptr) (void)(ptr)
+#endif
 
-#define NUM_TIMERS    1
-#define MAX_TICKS     1024
-#define MAX_RES       ODP_TIME_SEC
-#define MIN_RES       (100*ODP_TIME_USEC)
+/******************************************************************************
+ * Mutual exclusion in the absence of CAS16
+ *****************************************************************************/
 
+#ifndef ODP_ATOMIC_U128
+#define NUM_LOCKS 1024
+static _odp_atomic_flag_t locks[NUM_LOCKS]; /* Multiple locks per cache line! 
*/
+#define IDX2LOCK(idx) (&locks[(idx) % NUM_LOCKS])
+#endif
 
-typedef struct {
-       odp_spinlock_t lock;
-       timeout_t      *list;
-} tick_t;
-
-typedef struct {
-       int               allocated;
-       volatile int      active;
-       volatile uint64_t cur_tick;
-       timer_t           timerid;
-       odp_timer_t       timer_hdl;
-       odp_buffer_pool_t pool;
-       uint64_t          resolution_ns;
-       uint64_t          max_ticks;
-       tick_t            tick[MAX_TICKS];
-
-} timer_ring_t;
-
-typedef struct {
-       odp_spinlock_t lock;
-       int            num_timers;
-       timer_ring_t   timer[NUM_TIMERS];
-
-} timer_global_t;
+/******************************************************************************
+ * Translation between timeout and timeout header
+ *****************************************************************************/
 
-/* Global */
-static timer_global_t odp_timer;
+/**
+ * System timeout buffer (ODP_BUFFER_TYPE_TIEMOUT)
+ */
+typedef odp_buffer_t odp_timer_tmo_t;
 
-static void add_tmo(tick_t *tick, timeout_t *tmo)
+/** Translate from generic buffer to timeout */
+static inline odp_timer_tmo_t odp_tmo_from_buffer(odp_buffer_t buf)
 {
-       odp_spinlock_lock(&tick->lock);
-
-       tmo->next  = tick->list;
-       tick->list = tmo;
-
-       odp_spinlock_unlock(&tick->lock);
+       /* In this implementation, timeout == buffer */
+       return (odp_timer_tmo_t)buf;
 }
 
-static timeout_t *rem_tmo(tick_t *tick)
+/** Translate from timeout to generic buffer */
+static inline odp_buffer_t odp_buffer_from_tmo(odp_timer_tmo_t tmo)
 {
-       timeout_t *tmo;
+       /* In this implementation, buffer == timeout */
+       return (odp_buffer_t)tmo;
+}
 
-       odp_spinlock_lock(&tick->lock);
+static inline odp_timeout_hdr_t *odp_tmo_to_hdr(odp_timer_tmo_t tmo)
+{
+       odp_buffer_t buf = odp_buffer_from_tmo(tmo);
+       odp_timeout_hdr_t *tmo_hdr = (odp_timeout_hdr_t *)odp_buf_to_hdr(buf);
+       return tmo_hdr;
+}
 
-       tmo = tick->list;
+/******************************************************************************
+ * odp_timer abstract datatype
+ *****************************************************************************/
+
+typedef struct tick_buf_s {
+       odp_atomic_u64_t exp_tck;/* Expiration tick or TMO_xxx */
+       odp_buffer_t tmo_buf;/* ODP_BUFFER_INVALID if timer not active */
+#ifdef TB_NEEDS_PAD
+       uint32_t pad;/* Need to be able to access padding for successful CAS */
+#endif
+} tick_buf_t
+#ifdef ODP_ATOMIC_U128
+ODP_ALIGNED(16) /* 16-byte atomic operations need properly aligned addresses */
+#endif
+;
+
+ODP_STATIC_ASSERT(sizeof(tick_buf_t) == 16, "sizeof(tick_buf_t) == 16");
+
+typedef struct odp_timer_s {
+       void *user_ptr; /* User-defined pointer for odp_timer_tmo_t buffers */
+       odp_queue_t queue;/* Used for free list when timer is free */
+} odp_timer;
+
+static void timer_init(odp_timer *tim,
+               tick_buf_t *tb,
+               odp_queue_t _q,
+               void *_up)
+{
+       tim->queue = _q;
+       tim->user_ptr = _up;
+       tb->tmo_buf = ODP_BUFFER_INVALID;
+       /* All pad fields need a defined and constant value */
+       TB_SET_PAD(*tb);
+       /* Release the timer by setting timer state to inactive */
+       _odp_atomic_u64_store_mm(&tb->exp_tck, TMO_INACTIVE, _ODP_MEMMODEL_RLS);
+}
 
-       if (tmo)
-               tick->list = tmo->next;
+/* Teardown when timer is freed */
+static void timer_fini(odp_timer *tim, tick_buf_t *tb)
+{
+       assert(tb->exp_tck.v == TMO_UNUSED);
+       assert(tb->tmo_buf == ODP_BUFFER_INVALID);
+       tim->queue = ODP_QUEUE_INVALID;
+       tim->user_ptr = NULL;
+}
 
-       odp_spinlock_unlock(&tick->lock);
+static inline uint32_t get_next_free(odp_timer *tim)
+{
+       /* Reusing 'queue' for next free index */
+       return tim->queue;
+}
 
-       if (tmo)
-               tmo->next = NULL;
+static inline void set_next_free(odp_timer *tim, uint32_t nf)
+{
+       assert(tim->queue == ODP_QUEUE_INVALID);
+       /* Reusing 'queue' for next free index */
+       tim->queue = nf;
+}
 
-       return tmo;
+/******************************************************************************
+ * odp_timer_pool abstract datatype
+ * Inludes alloc and free timer
+ *****************************************************************************/
+
+typedef struct odp_timer_pool_s {
+/* Put frequently accessed fields in the first cache line */
+       odp_atomic_u64_t cur_tick;/* Current tick value */
+       uint64_t min_rel_tck;
+       uint64_t max_rel_tck;
+       uint64_t resolution_ns;
+       tick_buf_t *tick_buf; /* Expiration tick and timeout buffer */
+       odp_timer *timers; /* User pointer and queue handle (and lock) */
+       odp_atomic_u32_t high_wm;/* High watermark of allocated timers */
+       odp_spinlock_t itimer_running;
+       odp_spinlock_t lock;
+       bool shared;
+       uint32_t num_alloc;/* Current number of allocated timers */
+       uint32_t max_timers;/* Max number of timers */
+       uint32_t first_free;/* 0..max_timers-1 => free timer */
+       uint32_t tp_idx;/* Index into timer_pool array */
+       const char *name;
+       odp_buffer_pool_t buf_pool;
+       odp_shm_t shm;
+       timer_t timerid;
+       odp_timer_clk_src_t clk_src;
+} odp_timer_pool;
+
+#define MAX_TIMER_POOLS 255 /* Leave one for ODP_TIMER_INVALID */
+#define INDEX_BITS 24
+static odp_atomic_u32_t num_timer_pools;
+static odp_timer_pool *timer_pool[MAX_TIMER_POOLS];
+
+static inline odp_timer_pool *handle_to_tp(odp_timer_t hdl)
+{
+       uint32_t tp_idx = hdl >> INDEX_BITS;
+       if (odp_likely(tp_idx < MAX_TIMER_POOLS)) {
+               odp_timer_pool *tp = timer_pool[tp_idx];
+               if (odp_likely(tp != NULL))
+                       return timer_pool[tp_idx];
+       }
+       ODP_ABORT("Invalid timer handle %#x\n", hdl);
 }
 
-/**
- * Search and delete tmo entry from timeout list
- * return -1 : on error.. handle not in list
- *             0 : success
- */
-static int find_and_del_tmo(timeout_t **tmo, odp_timer_tmo_t handle)
+static inline uint32_t handle_to_idx(odp_timer_t hdl,
+               struct odp_timer_pool_s *tp)
 {
-       timeout_t *cur, *prev;
-       prev = NULL;
+       uint32_t idx = hdl & ((1U << INDEX_BITS) - 1U);
+       PREFETCH(&tp->tick_buf[idx]);
+       if (odp_likely(idx < odp_atomic_load_u32(&tp->high_wm)))
+               return idx;
+       ODP_ABORT("Invalid timer handle %#x\n", hdl);
+}
 
-       for (cur = *tmo; cur != NULL; prev = cur, cur = cur->next) {
-               if (cur->tmo_buf == handle) {
-                       if (prev == NULL)
-                               *tmo = cur->next;
-                       else
-                               prev->next = cur->next;
+static inline odp_timer_t tp_idx_to_handle(struct odp_timer_pool_s *tp,
+               uint32_t idx)
+{
+       assert(idx < (1U << INDEX_BITS));
+       return (tp->tp_idx << INDEX_BITS) | idx;
+}
 
-                       break;
-               }
+/* Forward declarations */
+static void itimer_init(odp_timer_pool *tp);
+static void itimer_fini(odp_timer_pool *tp);
+
+static odp_timer_pool *odp_timer_pool_new(
+       const char *_name,
+       odp_buffer_pool_t _bp,
+       uint64_t _res,
+       uint64_t _mintmo,
+       uint64_t _maxtmo,
+       uint32_t _maxtim,
+       bool _sh,
+       odp_timer_clk_src_t _cs)
+{
+       uint32_t tp_idx = odp_atomic_fetch_add_u32(&num_timer_pools, 1);
+       if (odp_unlikely(tp_idx >= MAX_TIMER_POOLS)) {
+               /* Restore the previous value */
+               odp_atomic_sub_u32(&num_timer_pools, 1);
+               errno = ENFILE; /* Table overflow */
+               return NULL;
        }
+       size_t sz0 = ODP_ALIGN_ROUNDUP(sizeof(odp_timer_pool),
+                       ODP_CACHE_LINE_SIZE);
+       size_t sz1 = ODP_ALIGN_ROUNDUP(sizeof(tick_buf_t) * _maxtim,
+                       ODP_CACHE_LINE_SIZE);
+       size_t sz2 = ODP_ALIGN_ROUNDUP(sizeof(odp_timer) * _maxtim,
+                       ODP_CACHE_LINE_SIZE);
+       odp_shm_t shm = odp_shm_reserve(_name, sz0 + sz1 + sz2,
+                       ODP_CACHE_LINE_SIZE, ODP_SHM_SW_ONLY);
+       if (odp_unlikely(shm == ODP_SHM_INVALID))
+               ODP_ABORT("%s: timer pool shm-alloc(%zuKB) failed\n",
+                         _name, (sz0 + sz1 + sz2) / 1024);
+       odp_timer_pool *tp = (odp_timer_pool *)odp_shm_addr(shm);
+       odp_atomic_init_u64(&tp->cur_tick, 0);
+       tp->name = strdup(_name);
+       tp->shm = shm;
+       tp->buf_pool = _bp;
+       tp->resolution_ns = _res;
+       tp->min_rel_tck = odp_timer_ns_to_tick(tp, _mintmo);
+       tp->max_rel_tck = odp_timer_ns_to_tick(tp, _maxtmo);
+       tp->num_alloc = 0;
+       odp_atomic_init_u32(&tp->high_wm, 0);
+       tp->max_timers = _maxtim;
+       tp->first_free = 0;
+       tp->shared = _sh;
+       tp->clk_src = _cs;
+       tp->tick_buf = (void *)((char *)odp_shm_addr(shm) + sz0);
+       tp->timers = (void *)((char *)odp_shm_addr(shm) + sz0 + sz1);
+       /* Initialize all odp_timer entries */
+       uint32_t i;
+       for (i = 0; i < tp->max_timers; i++) {
+               set_next_free(&tp->timers[i], i + 1);
+               tp->timers[i].user_ptr = NULL;
+       }
+       tp->tp_idx = tp_idx;
+       odp_spinlock_init(&tp->lock);
+       odp_spinlock_init(&tp->itimer_running);
+       timer_pool[tp_idx] = tp;
+       if (tp->clk_src == ODP_CLOCK_CPU)
+               itimer_init(tp);
+       return tp;
+}
 
-       if (!cur)
-               /* couldn't find tmo in list */
-               return -1;
-
-       /* application to free tmo_buf provided by absolute_tmo call */
-       return 0;
+static void odp_timer_pool_del(odp_timer_pool *tp)
+{
+       odp_spinlock_lock(&tp->lock);
+       timer_pool[tp->tp_idx] = NULL;
+       /* Wait for itimer thread to stop running */
+       odp_spinlock_lock(&tp->itimer_running);
+       if (tp->num_alloc != 0) {
+               /* It's a programming error to attempt to destroy a */
+               /* timer pool which is still in use */
+               ODP_ABORT("%s: timers in use\n", tp->name);
+       }
+       if (tp->clk_src == ODP_CLOCK_CPU)
+               itimer_fini(tp);
+       int rc = odp_shm_free(tp->shm);
+       if (rc != 0)
+               ODP_ABORT("Failed to free shared memory (%d)\n", rc);
 }
 
-int odp_timer_cancel_tmo(odp_timer_t timer_hdl, odp_timer_tmo_t tmo)
+static inline odp_timer_t timer_alloc(odp_timer_pool *tp,
+                                     odp_queue_t queue,
+                                     void *user_ptr)
 {
-       int id;
-       int tick_idx;
-       timeout_t *cancel_tmo;
-       odp_timeout_hdr_t *tmo_hdr;
-       tick_t *tick;
+       odp_timer_t hdl;
+       odp_spinlock_lock(&tp->lock);
+       if (odp_likely(tp->num_alloc < tp->max_timers)) {
+               tp->num_alloc++;
+               /* Remove first unused timer from free list */
+               assert(tp->first_free != tp->max_timers);
+               uint32_t idx = tp->first_free;
+               odp_timer *tim = &tp->timers[idx];
+               tp->first_free = get_next_free(tim);
+               /* Initialize timer */
+               timer_init(tim, &tp->tick_buf[idx], queue, user_ptr);
+               if (odp_unlikely(tp->num_alloc >
+                                odp_atomic_load_u32(&tp->high_wm)))
+                       /* Update high_wm last with release model to
+                        * ensure timer initialization is visible */
+                       _odp_atomic_u32_store_mm(&tp->high_wm,
+                                                tp->num_alloc,
+                                                _ODP_MEMMODEL_RLS);
+               hdl = tp_idx_to_handle(tp, idx);
+       } else {
+               errno = ENFILE; /* Reusing file table overflow */
+               hdl = ODP_TIMER_INVALID;
+       }
+       odp_spinlock_unlock(&tp->lock);
+       return hdl;
+}
 
-       /* get id */
-       id = (int)timer_hdl - 1;
+static odp_buffer_t timer_cancel(odp_timer_pool *tp,
+               uint32_t idx,
+               uint64_t new_state);
 
-       tmo_hdr = odp_timeout_hdr((odp_timeout_t) tmo);
-       /* get tmo_buf to cancel */
-       cancel_tmo = &tmo_hdr->meta;
+static inline odp_buffer_t timer_free(odp_timer_pool *tp, uint32_t idx)
+{
+       odp_timer *tim = &tp->timers[idx];
 
-       tick_idx = cancel_tmo->tick;
-       tick = &odp_timer.timer[id].tick[tick_idx];
+       /* Free the timer by setting timer state to unused and
+        * grab any timeout buffer */
+       odp_buffer_t old_buf = timer_cancel(tp, idx, TMO_UNUSED);
 
-       odp_spinlock_lock(&tick->lock);
-       /* search and delete tmo from tick list */
-       if (find_and_del_tmo(&tick->list, tmo) != 0) {
-               odp_spinlock_unlock(&tick->lock);
-               ODP_DBG("Couldn't find the tmo (%d) in tick list\n", (int)tmo);
-               return -1;
-       }
-       odp_spinlock_unlock(&tick->lock);
+       /* Destroy timer */
+       timer_fini(tim, &tp->tick_buf[idx]);
 
-       return 0;
+       /* Insert timer into free list */
+       odp_spinlock_lock(&tp->lock);
+       set_next_free(tim, tp->first_free);
+       tp->first_free = idx;
+       assert(tp->num_alloc != 0);
+       tp->num_alloc--;
+       odp_spinlock_unlock(&tp->lock);
+
+       return old_buf;
 }
 
-static void notify_function(union sigval sigval)
-{
-       uint64_t cur_tick;
-       timeout_t *tmo;
-       tick_t *tick;
-       timer_ring_t *timer;
+/******************************************************************************
+ * Operations on timers
+ * expire/reset/cancel timer
+ *****************************************************************************/
 
-       timer = sigval.sival_ptr;
+static bool timer_reset(uint32_t idx,
+               uint64_t abs_tck,
+               odp_buffer_t *tmo_buf,
+               odp_timer_pool *tp)
+{
+       bool success = true;
+       tick_buf_t *tb = &tp->tick_buf[idx];
+
+       if (tmo_buf == NULL || *tmo_buf == ODP_BUFFER_INVALID) {
+#ifdef ODP_ATOMIC_U128
+               tick_buf_t new, old;
+               do {
+                       /* Relaxed and non-atomic read of current values */
+                       old.exp_tck.v = tb->exp_tck.v;
+                       old.tmo_buf = tb->tmo_buf;
+                       TB_SET_PAD(old);
+                       /* Check if there actually is a timeout buffer
+                        * present */
+                       if (old.tmo_buf == ODP_BUFFER_INVALID) {
+                               /* Cannot reset a timer with neither old nor
+                                * new timeout buffer */
+                               success = false;
+                               break;
+                       }
+                       /* Set up new values */
+                       new.exp_tck.v = abs_tck;
+                       new.tmo_buf = old.tmo_buf;
+                       TB_SET_PAD(new);
+                       /* Atomic CAS will fail if we experienced torn reads,
+                        * retry update sequence until CAS succeeds */
+               } while (!_odp_atomic_u128_cmp_xchg_mm(
+                                       (_odp_atomic_u128_t *)tb,
+                                       (_uint128_t *)&old,
+                                       (_uint128_t *)&new,
+                                       _ODP_MEMMODEL_RLS,
+                                       _ODP_MEMMODEL_RLX));
+#else
+#ifdef __ARM_ARCH
+               /* Since barriers are not good for C-A15, we take an
+                * alternative approach using relaxed memory model */
+               uint64_t old;
+               /* Swap in new expiration tick, get back old tick which
+                * will indicate active/inactive timer state */
+               old = _odp_atomic_u64_xchg_mm(&tb->exp_tck, abs_tck,
+                       _ODP_MEMMODEL_RLX);
+               if (old == TMO_INACTIVE) {
+                       /* Timer was inactive (cancelled or expired),
+                        * we can't reset a timer without a timeout buffer.
+                        * Attempt to restore inactive state, we don't
+                        * want this timer to continue as active without
+                        * timeout as this will trigger unnecessary and
+                        * aborted expiration attempts.
+                        * We don't care if we fail, then some other thread
+                        * reset or cancelled the timer. Without any
+                        * synchronization between the threads, we have a
+                        * data race and the behavior is undefined */
+                       (void)_odp_atomic_u64_cmp_xchg_strong_mm(
+                                       &tb->exp_tck,
+                                       &abs_tck,
+                                       TMO_INACTIVE,
+                                       _ODP_MEMMODEL_RLX,
+                                       _ODP_MEMMODEL_RLX);
+                       success = false;
+               }
+#else
+               /* Take a related lock */
+               while (_odp_atomic_flag_tas(IDX2LOCK(idx)))
+                       (void)0;
+
+               /* Only if there is a timeout buffer can be reset the timer */
+               if (odp_likely(tb->tmo_buf != ODP_BUFFER_INVALID)) {
+                       /* Write the new expiration tick */
+                       tb->exp_tck.v = abs_tck;
+               } else {
+                       /* Cannot reset a timer with neither old nor new
+                        * timeout buffer */
+                       success = false;
+               }
 
-       if (timer->active == 0) {
-               ODP_DBG("Timer (%u) not active\n", timer->timer_hdl);
-               return;
+               /* Release the lock */
+               _odp_atomic_flag_clear(IDX2LOCK(idx));
+#endif
+#endif
+       } else {
+               /* We have a new timeout buffer which replaces any old one */
+               odp_buffer_t old_buf = ODP_BUFFER_INVALID;
+#ifdef ODP_ATOMIC_U128
+               tick_buf_t new, old;
+               new.exp_tck.v = abs_tck;
+               new.tmo_buf = *tmo_buf;
+               TB_SET_PAD(new);
+               /* We are releasing the new timeout buffer to some other
+                * thread */
+               _odp_atomic_u128_xchg_mm((_odp_atomic_u128_t *)tb,
+                                        (_uint128_t *)&new,
+                                        (_uint128_t *)&old,
+                                        _ODP_MEMMODEL_ACQ_RLS);
+               old_buf = old.tmo_buf;
+#else
+               /* Take a related lock */
+               while (_odp_atomic_flag_tas(IDX2LOCK(idx)))
+                       (void)0;
+
+               /* Swap in new buffer, save any old buffer */
+               old_buf = tb->tmo_buf;
+               tb->tmo_buf = *tmo_buf;
+
+               /* Write the new expiration tick */
+               tb->exp_tck.v = abs_tck;
+
+               /* Release the lock */
+               _odp_atomic_flag_clear(IDX2LOCK(idx));
+#endif
+               /* Return old timeout buffer */
+               *tmo_buf = old_buf;
        }
+       return success;
+}
 
-       /* ODP_DBG("Tick\n"); */
-
-       cur_tick = timer->cur_tick++;
-
-       odp_sync_stores();
-
-       tick = &timer->tick[cur_tick % MAX_TICKS];
+static odp_buffer_t timer_cancel(odp_timer_pool *tp,
+               uint32_t idx,
+               uint64_t new_state)
+{
+       tick_buf_t *tb = &tp->tick_buf[idx];
+       odp_buffer_t old_buf;
+
+#ifdef ODP_ATOMIC_U128
+       tick_buf_t new, old;
+       /* Update the timer state (e.g. cancel the current timeout) */
+       new.exp_tck.v = new_state;
+       /* Swap out the old buffer */
+       new.tmo_buf = ODP_BUFFER_INVALID;
+       TB_SET_PAD(new);
+       _odp_atomic_u128_xchg_mm((_odp_atomic_u128_t *)tb,
+                                (_uint128_t *)&new, (_uint128_t *)&old,
+                                _ODP_MEMMODEL_RLX);
+       old_buf = old.tmo_buf;
+#else
+       /* Take a related lock */
+       while (_odp_atomic_flag_tas(IDX2LOCK(idx)))
+               (void)0;
+
+       /* Update the timer state (e.g. cancel the current timeout) */
+       tb->exp_tck.v = new_state;
+
+       /* Swap out the old buffer */
+       old_buf = tb->tmo_buf;
+       tb->tmo_buf = ODP_BUFFER_INVALID;
+
+       /* Release the lock */
+       _odp_atomic_flag_clear(IDX2LOCK(idx));
+#endif
+       /* Return the old buffer */
+       return old_buf;
+}
 
-       while ((tmo = rem_tmo(tick)) != NULL) {
-               odp_queue_t  queue;
-               odp_buffer_t buf;
+static unsigned timer_expire(odp_timer_pool *tp, uint32_t idx, uint64_t tick)
+{
+       odp_timer *tim = &tp->timers[idx];
+       tick_buf_t *tb = &tp->tick_buf[idx];
+       odp_buffer_t tmo_buf = ODP_BUFFER_INVALID;
+       uint64_t exp_tck;
+#ifdef ODP_ATOMIC_U128
+       /* Atomic re-read for correctness */
+       exp_tck = _odp_atomic_u64_load_mm(&tb->exp_tck, _ODP_MEMMODEL_RLX);
+       /* Re-check exp_tck */
+       if (odp_likely(exp_tck <= tick)) {
+               /* Attempt to grab timeout buffer, replace with inactive timer
+                * and invalid buffer */
+               tick_buf_t new, old;
+               old.exp_tck.v = exp_tck;
+               old.tmo_buf = tb->tmo_buf;
+               TB_SET_PAD(old);
+               new.exp_tck.v = TMO_INACTIVE;
+               new.tmo_buf = ODP_BUFFER_INVALID;
+               TB_SET_PAD(new);
+               int succ = _odp_atomic_u128_cmp_xchg_mm(
+                               (_odp_atomic_u128_t *)tb,
+                               (_uint128_t *)&old, (_uint128_t *)&new,
+                               _ODP_MEMMODEL_RLS, _ODP_MEMMODEL_RLX);
+               if (succ)
+                       tmo_buf = old.tmo_buf;
+               /* Else CAS failed, something changed => skip timer
+                * this tick, it will be checked again next tick */
+       }
+       /* Else false positive, ignore */
+#else
+       /* Take a related lock */
+       while (_odp_atomic_flag_tas(IDX2LOCK(idx)))
+               (void)0;
+       /* Proper check for timer expired */
+       exp_tck = tb->exp_tck.v;
+       if (odp_likely(exp_tck <= tick)) {
+               /* Verify that there is a timeout buffer */
+               if (odp_likely(tb->tmo_buf != ODP_BUFFER_INVALID)) {
+                       /* Grab timeout buffer, replace with inactive timer
+                        * and invalid buffer */
+                       tmo_buf = tb->tmo_buf;
+                       tb->tmo_buf = ODP_BUFFER_INVALID;
+                       tb->exp_tck.v = TMO_INACTIVE;
+               }
+               /* Else somehow active timer without user buffer */
+       }
+       /* Else false positive, ignore */
+       /* Release the lock */
+       _odp_atomic_flag_clear(IDX2LOCK(idx));
+#endif
+       if (odp_likely(tmo_buf != ODP_BUFFER_INVALID)) {
+               /* Fill in metadata fields in system timeout buffer */
+               if (odp_buffer_type(tmo_buf) == ODP_BUFFER_TYPE_TIMEOUT) {
+                       /* Convert from buffer to timeout hdr */
+                       odp_timeout_hdr_t *tmo_hdr =
+                               odp_tmo_to_hdr(odp_tmo_from_buffer(tmo_buf));
+                       tmo_hdr->timer = tp_idx_to_handle(tp, idx);
+                       tmo_hdr->expiration = exp_tck;
+                       tmo_hdr->user_ptr = tim->user_ptr;
+               }
+               /* Else ignore buffers of other types */
+               /* Post the timeout to the destination queue */
+               int rc = odp_queue_enq(tim->queue, tmo_buf);
+               if (odp_unlikely(rc != 0))
+                       ODP_ABORT("Failed to enqueue timeout buffer (%d)\n",
+                                 rc);
+               return 1;
+       } else {
+               /* Else false positive, ignore */
+               return 0;
+       }
+}
 
-               queue = tmo->queue;
-               buf   = tmo->buf;
+static unsigned odp_timer_pool_expire(odp_timer_pool_t tpid, uint64_t tick)
+{
+       tick_buf_t *array = &tpid->tick_buf[0];
+       uint32_t high_wm = _odp_atomic_u32_load_mm(&tpid->high_wm,
+                       _ODP_MEMMODEL_ACQ);
+       unsigned nexp = 0;
+       uint32_t i;
+
+       for (i = 0; i < high_wm;) {
+#ifdef __ARM_ARCH
+               /* As a rare occurence, we can outsmart the HW prefetcher
+                * and the compiler (GCC -fprefetch-loop-arrays) with some
+                * tuned manual prefetching (32x16=512B ahead), seems to
+                * give 30% better performance on ARM C-A15 */
+               PREFETCH(&array[i + 32]);
+#endif
+               /* Non-atomic read for speed */
+               uint64_t exp_tck = array[i++].exp_tck.v;
+               if (odp_unlikely(exp_tck <= tick)) {
+                       /* Attempt to expire timer */
+                       nexp += timer_expire(tpid, i - 1, tick);
+               }
+       }
+       return nexp;
+}
 
-               if (buf != tmo->tmo_buf)
-                       odp_buffer_free(tmo->tmo_buf);
+/******************************************************************************
+ * POSIX timer support
+ * Functions that use Linux/POSIX per-process timers and related facilities
+ *****************************************************************************/
 
-               odp_queue_enq(queue, buf);
+static void timer_notify(sigval_t sigval)
+{
+       odp_timer_pool *tp = (odp_timer_pool *)sigval.sival_ptr;
+#ifdef __ARM_ARCH
+       odp_timer *array = &tp->timers[0];
+       uint32_t i;
+       /* Prefetch initial cache lines (match 32 above) */
+       for (i = 0; i < 32; i += ODP_CACHE_LINE_SIZE / sizeof(array[0]))
+               PREFETCH(&array[i]);
+#endif
+       uint64_t prev_tick = odp_atomic_fetch_inc_u64(&tp->cur_tick);
+       /* Attempt to acquire the lock, check if the old value was clear */
+       if (odp_spinlock_trylock(&tp->itimer_running)) {
+               /* Scan timer array, looking for timers to expire */
+               (void)odp_timer_pool_expire(tp, prev_tick);
+               odp_spinlock_unlock(&tp->itimer_running);
        }
+       /* Else skip scan of timers. cur_tick was updated and next itimer
+        * invocation will process older expiration ticks as well */
 }
 
-static void timer_start(timer_ring_t *timer)
+static void itimer_init(odp_timer_pool *tp)
 {
        struct sigevent   sigev;
        struct itimerspec ispec;
        uint64_t res, sec, nsec;
 
-       ODP_DBG("\nTimer (%u) starts\n", timer->timer_hdl);
+       ODP_DBG("Creating POSIX timer for timer pool %s, period %"
+               PRIu64" ns\n", tp->name, tp->resolution_ns);
 
        memset(&sigev, 0, sizeof(sigev));
        memset(&ispec, 0, sizeof(ispec));
 
        sigev.sigev_notify          = SIGEV_THREAD;
-       sigev.sigev_notify_function = notify_function;
-       sigev.sigev_value.sival_ptr = timer;
+       sigev.sigev_notify_function = timer_notify;
+       sigev.sigev_value.sival_ptr = tp;
 
-       if (timer_create(CLOCK_MONOTONIC, &sigev, &timer->timerid)) {
-               ODP_DBG("Timer create failed\n");
-               return;
-       }
+       if (timer_create(CLOCK_MONOTONIC, &sigev, &tp->timerid))
+               ODP_ABORT("timer_create() returned error %s\n",
+                         strerror(errno));
 
-       res  = timer->resolution_ns;
+       res  = tp->resolution_ns;
        sec  = res / ODP_TIME_SEC;
-       nsec = res - sec*ODP_TIME_SEC;
+       nsec = res - sec * ODP_TIME_SEC;
 
        ispec.it_interval.tv_sec  = (time_t)sec;
        ispec.it_interval.tv_nsec = (long)nsec;
        ispec.it_value.tv_sec     = (time_t)sec;
        ispec.it_value.tv_nsec    = (long)nsec;
 
-       if (timer_settime(timer->timerid, 0, &ispec, NULL)) {
-               ODP_DBG("Timer set failed\n");
-               return;
-       }
-
-       return;
+       if (timer_settime(&tp->timerid, 0, &ispec, NULL))
+               ODP_ABORT("timer_settime() returned error %s\n",
+                         strerror(errno));
 }
 
-int odp_timer_init_global(void)
+static void itimer_fini(odp_timer_pool *tp)
 {
-       ODP_DBG("Timer init ...");
-
-       memset(&odp_timer, 0, sizeof(timer_global_t));
-
-       odp_spinlock_init(&odp_timer.lock);
-
-       ODP_DBG("done\n");
-
-       return 0;
+       if (timer_delete(tp->timerid) != 0)
+               ODP_ABORT("timer_delete() returned error %s\n",
+                         strerror(errno));
 }
 
-int odp_timer_disarm_all(void)
+/******************************************************************************
+ * Public API functions
+ * Some parameter checks and error messages
+ * No modificatios of internal state
+ *****************************************************************************/
+odp_timer_pool_t
+odp_timer_pool_create(const char *name,
+                     odp_buffer_pool_t buf_pool,
+                     uint64_t resolution_ns,
+                     uint64_t min_timeout,
+                     uint64_t max_timeout,
+                     uint32_t num_timers,
+                     int shared,
+                     odp_timer_clk_src_t clk_src)
 {
-       int timers;
-       struct itimerspec ispec;
-
-       odp_spinlock_lock(&odp_timer.lock);
-
-       timers = odp_timer.num_timers;
-
-       ispec.it_interval.tv_sec  = 0;
-       ispec.it_interval.tv_nsec = 0;
-       ispec.it_value.tv_sec     = 0;
-       ispec.it_value.tv_nsec    = 0;
-
-       for (; timers >= 0; timers--) {
-               if (timer_settime(odp_timer.timer[timers].timerid,
-                                 0, &ispec, NULL)) {
-                       ODP_DBG("Timer reset failed\n");
-                       odp_spinlock_unlock(&odp_timer.lock);
-                       return -1;
-               }
-               odp_timer.num_timers--;
-       }
-
-       odp_spinlock_unlock(&odp_timer.lock);
-
-       return 0;
+       /* Verify that buffer pool can be used for timeouts */
+       odp_buffer_t buf = odp_buffer_alloc(buf_pool);
+       if (buf == ODP_BUFFER_INVALID)
+               ODP_ABORT("%s: Failed to allocate buffer\n", name);
+       if (odp_buffer_type(buf) != ODP_BUFFER_TYPE_TIMEOUT)
+               ODP_ABORT("%s: Buffer pool wrong type\n", name);
+       odp_buffer_free(buf);
+       odp_timer_pool_t tp = odp_timer_pool_new(name, buf_pool, resolution_ns,
+                             min_timeout, max_timeout, num_timers, shared,
+                             clk_src);
+       return tp;
 }
 
-odp_timer_t odp_timer_create(const char *name, odp_buffer_pool_t pool,
-                            uint64_t resolution_ns, uint64_t min_ns,
-                            uint64_t max_ns)
+void odp_timer_pool_start(void)
 {
-       uint32_t id;
-       timer_ring_t *timer;
-       odp_timer_t timer_hdl;
-       int i;
-       uint64_t max_ticks;
-       (void) name;
-
-       if (resolution_ns < MIN_RES)
-               resolution_ns = MIN_RES;
-
-       if (resolution_ns > MAX_RES)
-               resolution_ns = MAX_RES;
-
-       max_ticks = max_ns / resolution_ns;
-
-       if (max_ticks > MAX_TICKS) {
-               ODP_DBG("Maximum timeout too long: %"PRIu64" ticks\n",
-                       max_ticks);
-               return ODP_TIMER_INVALID;
-       }
-
-       if (min_ns < resolution_ns) {
-               ODP_DBG("Min timeout %"PRIu64" ns < resolution %"PRIu64" ns\n",
-                       min_ns, resolution_ns);
-               return ODP_TIMER_INVALID;
-       }
-
-       odp_spinlock_lock(&odp_timer.lock);
-
-       if (odp_timer.num_timers >= NUM_TIMERS) {
-               odp_spinlock_unlock(&odp_timer.lock);
-               ODP_DBG("All timers allocated\n");
-               return ODP_TIMER_INVALID;
-       }
-
-       for (id = 0; id < NUM_TIMERS; id++) {
-               if (odp_timer.timer[id].allocated == 0)
-                       break;
-       }
-
-       timer = &odp_timer.timer[id];
-       timer->allocated = 1;
-       odp_timer.num_timers++;
-
-       odp_spinlock_unlock(&odp_timer.lock);
-
-       timer_hdl = id + 1;
-
-       timer->timer_hdl     = timer_hdl;
-       timer->pool          = pool;
-       timer->resolution_ns = resolution_ns;
-       timer->max_ticks     = MAX_TICKS;
-
-       for (i = 0; i < MAX_TICKS; i++) {
-               odp_spinlock_init(&timer->tick[i].lock);
-               timer->tick[i].list = NULL;
-       }
-
-       timer->active = 1;
-       odp_sync_stores();
-
-       timer_start(timer);
-
-       return timer_hdl;
+       /* Nothing to do here, timer pools are started by the create call */
 }
 
-odp_timer_tmo_t odp_timer_absolute_tmo(odp_timer_t timer_hdl, uint64_t 
tmo_tick,
-                                      odp_queue_t queue, odp_buffer_t buf)
+void odp_timer_pool_destroy(odp_timer_pool_t tpid)
 {
-       int id;
-       uint64_t tick;
-       uint64_t cur_tick;
-       timeout_t *new_tmo;
-       odp_buffer_t tmo_buf;
-       odp_timeout_hdr_t *tmo_hdr;
-       timer_ring_t *timer;
-
-       id = (int)timer_hdl - 1;
-       timer = &odp_timer.timer[id];
+       odp_timer_pool_del(tpid);
+}
 
-       cur_tick = timer->cur_tick;
-       if (tmo_tick <= cur_tick) {
-               ODP_DBG("timeout too close\n");
-               return ODP_TIMER_TMO_INVALID;
-       }
+uint64_t odp_timer_tick_to_ns(odp_timer_pool_t tpid, uint64_t ticks)
+{
+       return ticks * tpid->resolution_ns;
+}
 
-       if ((tmo_tick - cur_tick) > MAX_TICKS) {
-               ODP_DBG("timeout too far: cur %"PRIu64" tmo %"PRIu64"\n",
-                       cur_tick, tmo_tick);
-               return ODP_TIMER_TMO_INVALID;
-       }
+uint64_t odp_timer_ns_to_tick(odp_timer_pool_t tpid, uint64_t ns)
+{
+       return (uint64_t)(ns / tpid->resolution_ns);
+}
 
-       tick = tmo_tick % MAX_TICKS;
+uint64_t odp_timer_current_tick(odp_timer_pool_t tpid)
+{
+       /* Relaxed atomic read for lowest overhead */
+       return odp_atomic_load_u64(&tpid->cur_tick);
+}
 
-       tmo_buf = odp_buffer_alloc(timer->pool);
-       if (tmo_buf == ODP_BUFFER_INVALID) {
-               ODP_DBG("tmo buffer alloc failed\n");
-               return ODP_TIMER_TMO_INVALID;
+size_t odp_timer_pool_info(odp_timer_pool_t tpid,
+                          odp_timer_pool_info_t *buf,
+                          size_t buf_size)
+{
+       size_t needs;
+       buf->resolution = tpid->resolution_ns;
+       buf->min_tmo = tpid->min_rel_tck;
+       buf->max_tmo = tpid->max_rel_tck;
+       buf->num_timers = tpid->max_timers;
+       buf->cur_timers = tpid->num_alloc;
+       buf->hwm_timers = odp_atomic_load_u32(&tpid->high_wm);
+       buf->shared = tpid->shared;
+       /* Compute how large buffer is needed */
+       needs = offsetof(struct odp_timer_pool_info_s, name) +
+               strlen(tpid->name) + 1;
+       if (buf_size >= needs) {
+               /* Provided buffer is large enough */
+               strcpy(buf->name, tpid->name);
+               return needs;
+       } else {
+               /* Provided buffer is too small */
+               size_t siz = sizeof(buf->name);
+               /* Truncate name when copying into buffer */
+               strncpy(buf->name, tpid->name, siz - 1);
+               buf->name[siz] = 0;
+               return buf_size;
        }
-
-       tmo_hdr = odp_timeout_hdr((odp_timeout_t) tmo_buf);
-       new_tmo = &tmo_hdr->meta;
-
-       new_tmo->timer_id = id;
-       new_tmo->tick     = (int)tick;
-       new_tmo->tmo_tick = tmo_tick;
-       new_tmo->queue    = queue;
-       new_tmo->tmo_buf  = tmo_buf;
-
-       if (buf != ODP_BUFFER_INVALID)
-               new_tmo->buf = buf;
-       else
-               new_tmo->buf = tmo_buf;
-
-       add_tmo(&timer->tick[tick], new_tmo);
-
-       return tmo_buf;
 }
 
-uint64_t odp_timer_tick_to_ns(odp_timer_t timer_hdl, uint64_t ticks)
+odp_timer_t odp_timer_alloc(odp_timer_pool_t tpid,
+                           odp_queue_t queue,
+                           void *user_ptr)
 {
-       uint32_t id;
-
-       id = timer_hdl - 1;
-       return ticks * odp_timer.timer[id].resolution_ns;
+       if (odp_unlikely(queue == ODP_QUEUE_INVALID))
+               ODP_ABORT("%s: Invalid queue handle\n", tpid->name);
+       /* We don't care about the validity of user_ptr because we will not
+        * attempt to dereference it */
+       odp_timer_t hdl = timer_alloc(tpid, queue, user_ptr);
+       if (odp_likely(hdl != ODP_TIMER_INVALID)) {
+               /* Success */
+               return hdl;
+       }
+       /* errno set by timer_alloc() */
+       return ODP_TIMER_INVALID;
 }
 
-uint64_t odp_timer_ns_to_tick(odp_timer_t timer_hdl, uint64_t ns)
+uint64_t odp_timer_free(odp_timer_t hdl, odp_buffer_t *tmo_buf)
 {
-       uint32_t id;
-
-       id = timer_hdl - 1;
-       return ns / odp_timer.timer[id].resolution_ns;
+       odp_timer_pool *tp = handle_to_tp(hdl);
+       uint32_t idx = handle_to_idx(hdl, tp);
+       odp_buffer_t old_buf = timer_free(tp, idx);
+       /* Only overwrite *tmo_buf if we are actually returning a timeout
+        * buffer */
+       if (old_buf != ODP_BUFFER_INVALID)
+               *tmo_buf = old_buf;
+       /* Return a special value that will not match any timeout expiration
+        * tick and thus help identify stale timeouts */
+       return ODP_TICK_INVALID;
 }
 
-uint64_t odp_timer_resolution(odp_timer_t timer_hdl)
+uint64_t odp_timer_set_abs(odp_timer_t hdl,
+                          uint64_t abs_tck,
+                          odp_buffer_t *tmo_buf)
 {
-       uint32_t id;
-
-       id = timer_hdl - 1;
-       return odp_timer.timer[id].resolution_ns;
+       odp_timer_pool *tp = handle_to_tp(hdl);
+       uint32_t idx = handle_to_idx(hdl, tp);
+       uint64_t cur_tick = odp_atomic_load_u64(&tp->cur_tick);
+       if (odp_unlikely(abs_tck < cur_tick + tp->min_rel_tck))
+               return ODP_TICK_TOOEARLY;
+       if (odp_unlikely(abs_tck > cur_tick + tp->max_rel_tck))
+               return ODP_TICK_TOOLATE;
+       /* Return either the requested tick value when successful or a special
+        * value that will not match any timeout for errors */
+       return timer_reset(idx, abs_tck, tmo_buf, tp) ?
+               abs_tck : ODP_TICK_INVALID;
 }
 
-uint64_t odp_timer_maximum_tmo(odp_timer_t timer_hdl)
+uint64_t odp_timer_set_rel(odp_timer_t hdl,
+                          uint64_t rel_tck,
+                          odp_buffer_t *tmo_buf)
 {
-       uint32_t id;
-
-       id = timer_hdl - 1;
-       return odp_timer.timer[id].max_ticks;
+       odp_timer_pool *tp = handle_to_tp(hdl);
+       uint32_t idx = handle_to_idx(hdl, tp);
+       if (odp_unlikely(rel_tck < tp->min_rel_tck))
+               return ODP_TICK_TOOEARLY;
+       if (odp_unlikely(rel_tck > tp->max_rel_tck))
+               return ODP_TICK_TOOLATE;
+       uint64_t abs_tck = odp_atomic_load_u64(&tp->cur_tick) + rel_tck;
+       /* Return either the requested tick value when successful or a special
+        * value that will not match any timeout for errors */
+       return timer_reset(idx, abs_tck, tmo_buf, tp) ?
+               abs_tck : ODP_TICK_INVALID;
 }
 
-uint64_t odp_timer_current_tick(odp_timer_t timer_hdl)
+uint64_t odp_timer_cancel(odp_timer_t hdl, odp_buffer_t *tmo_buf)
 {
-       uint32_t id;
-
-       id = timer_hdl - 1;
-       return odp_timer.timer[id].cur_tick;
+       odp_timer_pool *tp = handle_to_tp(hdl);
+       uint32_t idx = handle_to_idx(hdl, tp);
+       *tmo_buf = timer_cancel(tp, idx, TMO_INACTIVE);
+       /* Return a special value that will not match any timeout expiration
+        * tick and thus help identify stale timeouts */
+       return ODP_TICK_INVALID;
 }
 
-odp_timeout_t odp_timeout_from_buffer(odp_buffer_t buf)
+int odp_timer_tmo_metadata(odp_buffer_t buf,
+               odp_timer_t *hdl_p,
+               uint64_t *exp_tck_p,
+               void **user_ptr_p)
 {
-       return (odp_timeout_t) buf;
+       if (odp_likely(odp_buffer_type(buf) == ODP_BUFFER_TYPE_TIMEOUT)) {
+               odp_timeout_hdr_t *tmo_hdr =
+                       odp_tmo_to_hdr(odp_tmo_from_buffer(buf));
+               odp_timer_t timer = tmo_hdr->timer;
+               uint64_t expiration = tmo_hdr->expiration;
+               void *user_ptr = tmo_hdr->user_ptr;
+               if (odp_likely(hdl_p != NULL))
+                       *hdl_p = timer;
+               if (odp_likely(exp_tck_p != NULL))
+                       *exp_tck_p = expiration;
+               if (odp_likely(user_ptr_p != NULL))
+                       *user_ptr_p = user_ptr;
+               return 1;
+       } else {
+               /* Not a buffer of the appropriate type */
+               return 0;
+       }
 }
 
-uint64_t odp_timeout_tick(odp_timeout_t tmo)
+int odp_timer_init_global(void)
 {
-       odp_timeout_hdr_t *tmo_hdr = odp_timeout_hdr(tmo);
-       return tmo_hdr->meta.tmo_tick;
+#ifndef ODP_ATOMIC_U128
+       uint32_t i;
+       for (i = 0; i < NUM_LOCKS; i++)
+               _odp_atomic_flag_clear(&locks[i]);
+#else
+       ODP_DBG("Using lock-less timer implementation\n");
+#endif
+       odp_atomic_init_u32(&num_timer_pools, 0);
+       return 0;
 }
-- 
1.9.1


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