Author: Tobias Weber <tobias_webe...@gmx.de>
Branch: c8-adaptive-trx-length
Changeset: r2051:3ffb90144a7f
Date: 2017-05-01 18:08 +0200
http://bitbucket.org/pypy/stmgc/changeset/3ffb90144a7f/
Log: Implement exponential build up and back off in transaction length
diff --git a/c8/stm/core.c b/c8/stm/core.c
--- a/c8/stm/core.c
+++ b/c8/stm/core.c
@@ -289,11 +289,6 @@
/* conflict! */
dprintf(("_stm_validate() failed for obj %p\n", obj));
- /* disregard race conditions */
- if (stm_global_conflicts < stm_max_conflicts) {
- stm_global_conflicts += 1;
- }
-
/* first reset all modified objects from the backup
copies as soon as the first conflict is detected;
then we will proceed below to update our segment
@@ -352,6 +347,7 @@
}
if (thread_local_for_logging != NULL) {
+ stm_transaction_length_handle_validation(thread_local_for_logging,
needs_abort);
stop_timer_and_publish_for_thread(
thread_local_for_logging, STM_DURATION_VALIDATION);
}
diff --git a/c8/stm/nursery.c b/c8/stm/nursery.c
--- a/c8/stm/nursery.c
+++ b/c8/stm/nursery.c
@@ -4,6 +4,7 @@
#endif
#include "finalizer.h"
+#include <math.h>
/************************************************************/
@@ -14,30 +15,62 @@
static uintptr_t _stm_nursery_start;
#define DEFAULT_FILL_MARK_NURSERY_BYTES (NURSERY_SIZE / 4)
-#define LARGE_FILL_MARK_NURSERY_BYTES 0x3000000000000000L;
+// just double the size at max
+// #define LARGE_FILL_MARK_NURSERY_BYTES DEFAULT_FILL_MARK_NURSERY_BYTES
+#define LARGE_FILL_MARK_NURSERY_BYTES 0x10000000000L
+// #define LARGE_FILL_MARK_NURSERY_BYTES 0x1000000000000000L
-// uintptr_t stm_fill_mark_nursery_bytes = DEFAULT_FILL_MARK_NURSERY_BYTES;
-uintptr_t stm_fill_mark_nursery_bytes = LARGE_FILL_MARK_NURSERY_BYTES;
+uintptr_t stm_fill_mark_nursery_bytes = DEFAULT_FILL_MARK_NURSERY_BYTES;
+// uintptr_t stm_fill_mark_nursery_bytes = LARGE_FILL_MARK_NURSERY_BYTES;
-static uint32_t stm_max_conflicts = 1000;
-static uint32_t stm_global_conflicts = 0;
+static float stm_default_relative_transaction_length = 0.000001;
+static float *stm_relative_transaction_length_pointer =
+ &stm_default_relative_transaction_length;
+
+static float get_new_transaction_length(bool aborts, float previous) {
+ float new = previous;
+ if (aborts) {
+ if (previous > 0.000001) {
+ new = previous / 2;
+ } else if (previous > 0) {
+ new = 0;
+ }
+ } else {
+ if (previous - 0.0000001 < 0) {
+ new = 0.000001;
+ } else if (previous < 1) {
+ new = previous * 2;
+ }
+ }
+ return new;
+}
+
+static void stm_transaction_length_handle_validation(stm_thread_local_t *tl,
bool aborts) {
+ float actual = *stm_relative_transaction_length_pointer;
+ float expected;
+ do {
+ expected = actual;
+ float new = get_new_transaction_length(aborts, actual);
+ __atomic_exchange(
+ stm_relative_transaction_length_pointer, &new, &actual,
__ATOMIC_RELAXED);
+ } while (fabs(actual - expected) > 0.0000001);
+}
static void stm_update_transaction_length(void) {
- float relative_conflicts = (float) stm_global_conflicts /
stm_max_conflicts;
- uintptr_t max_reduction =
- LARGE_FILL_MARK_NURSERY_BYTES - DEFAULT_FILL_MARK_NURSERY_BYTES;
- stm_fill_mark_nursery_bytes =
- LARGE_FILL_MARK_NURSERY_BYTES - (relative_conflicts * max_reduction);
+ float relative_additional_length =
*stm_relative_transaction_length_pointer;
+ stm_fill_mark_nursery_bytes = DEFAULT_FILL_MARK_NURSERY_BYTES +
+ (uintptr_t)(LARGE_FILL_MARK_NURSERY_BYTES *
relative_additional_length);
if (timing_enabled()) {
struct timespec relative_length = {
- .tv_sec = (int)relative_conflicts,
- .tv_nsec = (int)(fmod(relative_conflicts, 1) * 1000000000),
+ .tv_sec = (int)relative_additional_length,
+ .tv_nsec = (int)(fmod(relative_additional_length, 1) * 1000000000),
};
stm_duration_payload(relative_length);
stmcb_timing_event(
STM_SEGMENT->running_thread,
STM_SINGLE_THREAD_MODE_ADAPTIVE,
&stm_duration_payload);
+ }
}
diff --git a/c8/stm/nursery.h b/c8/stm/nursery.h
--- a/c8/stm/nursery.h
+++ b/c8/stm/nursery.h
@@ -59,6 +59,7 @@
static uint32_t stm_max_conflicts;
static uint32_t stm_global_conflicts;
+static void stm_transaction_length_handle_validation(stm_thread_local_t *tl,
bool aborts);
static void stm_update_transaction_length(void);
#endif
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