Author: Armin Rigo <ar...@tunes.org>
Branch:
Changeset: r887:e0e14e5a9b5d
Date: 2014-02-27 00:42 +0100
http://bitbucket.org/pypy/stmgc/changeset/e0e14e5a9b5d/
Log: Fix the big slowness that duhton's list_transaction sometimes shows.
diff --git a/c7/stm/contention.c b/c7/stm/contention.c
--- a/c7/stm/contention.c
+++ b/c7/stm/contention.c
@@ -82,7 +82,9 @@
/* wait, hopefully until the other thread broadcasts "I'm
done aborting" (spurious wake-ups are ok). */
+ dprintf(("contention: wait C_SAFE_POINT...\n"));
cond_wait(C_SAFE_POINT);
+ dprintf(("contention: done\n"));
cond_broadcast(C_RESUME);
diff --git a/c7/stm/core.c b/c7/stm/core.c
--- a/c7/stm/core.c
+++ b/c7/stm/core.c
@@ -171,7 +171,7 @@
#endif
STM_PSEGMENT->shadowstack_at_start_of_transaction = tl->shadowstack;
STM_PSEGMENT->threadlocal_at_start_of_transaction = tl->thread_local_obj;
- STM_SEGMENT->nursery_end = NURSERY_END;
+ assert(STM_SEGMENT->nursery_end == NURSERY_END);
dprintf(("start_transaction\n"));
@@ -478,12 +478,28 @@
contention.c, we use a broadcast, to make sure that all threads are
signalled, including the one that requested an abort, if any.
Moreover, we wake up any thread waiting for this one to do a safe
- point, if any.
+ point, if any (in _finish_transaction above). Finally, it's
+ possible that we reach this place from the middle of a piece of
+ code like wait_for_other_safe_points() which ends in broadcasting
+ C_RESUME; we must make sure to broadcast it.
*/
cond_broadcast(C_RELEASE_THREAD_SEGMENT);
+ cond_broadcast(C_RESUME);
mutex_unlock();
+ /* It seems to be a good idea, at least in some examples, to sleep
+ one microsecond here before retrying. Otherwise, what was
+ observed is that the transaction very often restarts too quickly
+ for contention.c to react, and before it can do anything, we have
+ again recreated in this thread a similar situation to the one
+ that caused contention. Anyway, usleep'ing in case of abort
+ doesn't seem like a very bad idea. If there are more threads
+ than segments, it should also make sure another thread gets the
+ segment next.
+ */
+ usleep(1);
+
assert(jmpbuf_ptr != NULL);
assert(jmpbuf_ptr != (stm_jmpbuf_t *)-1); /* for tests only */
__builtin_longjmp(*jmpbuf_ptr, 1);
diff --git a/c7/stm/sync.c b/c7/stm/sync.c
--- a/c7/stm/sync.c
+++ b/c7/stm/sync.c
@@ -323,6 +323,7 @@
assert(STM_PSEGMENT->safe_point == SP_RUNNING);
while (STM_SEGMENT->nursery_end == NSE_SIGNAL) {
+ dprintf(("collectable_safe_point...\n"));
STM_PSEGMENT->safe_point = SP_SAFE_POINT_CAN_COLLECT;
STM_SEGMENT->nursery_end = NURSERY_END;
@@ -334,4 +335,5 @@
STM_PSEGMENT->safe_point = SP_RUNNING;
}
+ dprintf(("collectable_safe_point done\n"));
}
diff --git a/duhton/glob.c b/duhton/glob.c
--- a/duhton/glob.c
+++ b/duhton/glob.c
@@ -705,9 +705,11 @@
int ms = DuInt_AsInt(obj);
struct timeval t;
+ fprintf(stderr, "[sleeping %d ms]\n", ms);
t.tv_sec = ms / 1000;
t.tv_usec = (ms % 1000) * 1000;
select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &t);
+ fprintf(stderr, "[slept %d ms]\n", ms);
return Du_None;
}
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