Implement a new internal function timer_res_init() to detect the max timer resolution without overrun at the ODP init stage. It will check timer resolution from 1ms to 100us, 10us...1ns until the timer is overrun.
Signed-off-by: Kevin Wang <[email protected]> --- platform/linux-generic/odp_timer.c | 95 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) diff --git a/platform/linux-generic/odp_timer.c b/platform/linux-generic/odp_timer.c index 53fec08..9b884ea 100644 --- a/platform/linux-generic/odp_timer.c +++ b/platform/linux-generic/odp_timer.c @@ -70,6 +70,9 @@ static _odp_atomic_flag_t locks[NUM_LOCKS]; /* Multiple locks per cache line! */ #define IDX2LOCK(idx) (&locks[(idx) % NUM_LOCKS]) #endif +/* Timer resolution in nanoseconds */ +static uint64_t timer_res; + /****************************************************************************** * Translation between timeout buffer and timeout header *****************************************************************************/ @@ -188,6 +191,7 @@ typedef struct odp_timer_pool_s { #define MAX_TIMER_POOLS 255 /* Leave one for ODP_TIMER_INVALID */ #define INDEX_BITS 24 +#define TIMER_RES_TEST_LOOP_COUNT 10 static odp_atomic_u32_t num_timer_pools; static odp_timer_pool *timer_pool[MAX_TIMER_POOLS]; @@ -738,6 +742,81 @@ static void *timer_thread(void *arg) return NULL; } +/* Get the max timer resolution without overrun and fill in timer_res variable. + * + * Set timer's interval with candidate resolutions to get the max resolution + * that the timer would not be overrun. + * The candidate resolution value is from 1ms to 100us, 10us...1ns etc. + */ +static int timer_res_init(void) +{ + struct sigevent sigev; + timer_t timerid; + uint64_t res, sec, nsec; + struct itimerspec ispec; + sigset_t sigset; + siginfo_t si; + int loop_cnt; + struct timespec tmo; + + sigev.sigev_notify = SIGEV_THREAD_ID; + sigev._sigev_un._tid = (pid_t)syscall(SYS_gettid); + sigev.sigev_signo = SIGUSR1; + + /* Create timer */ + if (timer_create(CLOCK_MONOTONIC, &sigev, &timerid)) + ODP_ABORT("timer_create() returned error %s\n", + strerror(errno)); + + /* Timer resolution start from 1ms */ + res = ODP_TIME_MSEC_IN_NS; + /* Set initial value of timer_res */ + timer_res = res; + sigemptyset(&sigset); + /* Add SIGUSR1 to sigset */ + sigaddset(&sigset, SIGUSR1); + sigprocmask(SIG_BLOCK, &sigset, NULL); + + while (res > 0) { + /* Loop for 10 times to test the result */ + loop_cnt = TIMER_RES_TEST_LOOP_COUNT; + sec = res / ODP_TIME_SEC_IN_NS; + nsec = res - sec * ODP_TIME_SEC_IN_NS; + + memset(&ispec, 0, sizeof(ispec)); + 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(timerid, 0, &ispec, NULL)) + ODP_ABORT("timer_settime() returned error %s\n", + strerror(errno)); + /* Set signal wait timeout to 10*res */ + tmo.tv_sec = 0; + tmo.tv_nsec = res * 10; + while (loop_cnt--) { + if (sigtimedwait(&sigset, &si, &tmo) > 0) { + if (timer_getoverrun(timerid)) + /* overrun at this resolution */ + /* goto the end */ + goto timer_res_init_done; + } + } + /* Set timer_res */ + timer_res = res; + /* Test the next timer resolution candidate */ + res /= 10; + } +timer_res_init_done: + if (timer_delete(timerid) != 0) + ODP_ABORT("timer_delete() returned error %s\n", + strerror(errno)); + sigemptyset(&sigset); + sigprocmask(SIG_BLOCK, &sigset, NULL); + return 0; +} + static void itimer_init(odp_timer_pool *tp) { struct sigevent sigev; @@ -795,6 +874,20 @@ static void itimer_fini(odp_timer_pool *tp) * Some parameter checks and error messages * No modificatios of internal state *****************************************************************************/ +int odp_timer_capability(odp_timer_clk_src_t clk_src, + odp_timer_capability_t *capa) +{ + int ret = 0; + + if (clk_src == ODP_CLOCK_CPU) { + capa->res_ns = timer_res; + } else { + ODP_ERR("ODP timer system doesn't support external clock source currently\n"); + ret = -1; + } + return ret; +} + odp_timer_pool_t odp_timer_pool_create(const char *name, const odp_timer_pool_param_t *param) @@ -1003,6 +1096,8 @@ int odp_timer_init_global(void) #endif odp_atomic_init_u32(&num_timer_pools, 0); + timer_res_init(); + block_sigalarm(); return 0; -- 1.9.1
