From 953de20fc9980fa0768732cab42692733f8c0bfa Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Thu, 22 Oct 2020 15:54:28 -0400
Subject: [PATCH] rts/Stats: Protect with mutex
While on face value this seems a bit heavy, I think it's far better than
enforcing ordering on every access.
---
rts/Stats.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 52 insertions(+), 6 deletions(-)
diff --git a/rts/Stats.c b/rts/Stats.c
index 7b30282d4487..8fb546715157 100644
--- a/rts/Stats.c
+++ b/rts/Stats.c
@@ -26,6 +26,11 @@
#include <string.h> // for memset
+#if defined(THREADED_RTS)
+// Protects all statistics below
+Mutex stats_mutex;
+#endif
+
static Time
start_init_cpu, start_init_elapsed,
end_init_cpu, end_init_elapsed,
@@ -101,6 +106,10 @@ mut_user_time_during_RP( void )
void
initStats0(void)
{
+#if defined(THREADED_RTS)
+ initMutex(&stats_mutex);
+#endif
+
start_init_cpu = 0;
start_init_elapsed = 0;
end_init_cpu = 0;
@@ -262,9 +271,11 @@ stat_endInit(void)
void
stat_startExit(void)
{
+ ACQUIRE_LOCK(&stats_mutex);
getProcessTimes(&start_exit_cpu, &start_exit_elapsed);
start_exit_gc_elapsed = stats.gc_elapsed_ns;
start_exit_gc_cpu = stats.gc_cpu_ns;
+ RELEASE_LOCK(&stats_mutex);
}
/* -----------------------------------------------------------------------------
@@ -275,7 +286,9 @@ stat_startExit(void)
void
stat_endExit(void)
{
+ ACQUIRE_LOCK(&stats_mutex);
getProcessTimes(&end_exit_cpu, &end_exit_elapsed);
+ RELEASE_LOCK(&stats_mutex);
}
void
@@ -287,8 +300,10 @@ stat_startGCSync (gc_thread *gct)
void
stat_startNonmovingGc ()
{
+ ACQUIRE_LOCK(&stats_mutex);
start_nonmoving_gc_cpu = getCurrentThreadCPUTime();
start_nonmoving_gc_elapsed = getProcessCPUTime();
+ RELEASE_LOCK(&stats_mutex);
}
void
@@ -296,6 +311,8 @@ stat_endNonmovingGc ()
{
Time cpu = getCurrentThreadCPUTime();
Time elapsed = getProcessCPUTime();
+
+ ACQUIRE_LOCK(&stats_mutex);
stats.gc.nonmoving_gc_elapsed_ns = elapsed - start_nonmoving_gc_elapsed;
stats.nonmoving_gc_elapsed_ns += stats.gc.nonmoving_gc_elapsed_ns;
@@ -305,12 +322,15 @@ stat_endNonmovingGc ()
stats.nonmoving_gc_max_elapsed_ns =
stg_max(stats.gc.nonmoving_gc_elapsed_ns,
stats.nonmoving_gc_max_elapsed_ns);
+ RELEASE_LOCK(&stats_mutex);
}
void
stat_startNonmovingGcSync ()
{
+ ACQUIRE_LOCK(&stats_mutex);
start_nonmoving_gc_sync_elapsed = getProcessElapsedTime();
+ RELEASE_LOCK(&stats_mutex);
traceConcSyncBegin();
}
@@ -318,11 +338,13 @@ void
stat_endNonmovingGcSync ()
{
Time end_elapsed = getProcessElapsedTime();
+ ACQUIRE_LOCK(&stats_mutex);
stats.gc.nonmoving_gc_sync_elapsed_ns = end_elapsed - start_nonmoving_gc_sync_elapsed;
stats.nonmoving_gc_sync_elapsed_ns += stats.gc.nonmoving_gc_sync_elapsed_ns;
stats.nonmoving_gc_sync_max_elapsed_ns =
stg_max(stats.gc.nonmoving_gc_sync_elapsed_ns,
stats.nonmoving_gc_sync_max_elapsed_ns);
+ RELEASE_LOCK(&stats_mutex);
traceConcSyncEnd();
}
@@ -437,6 +459,8 @@ stat_endGC (Capability *cap, gc_thread *initiating_gct, W_ live, W_ copied, W_ s
W_ mut_spin_spin, W_ mut_spin_yield, W_ any_work, W_ no_work,
W_ scav_find_work)
{
+ ACQUIRE_LOCK(&stats_mutex);
+
// -------------------------------------------------
// Collect all the stats about this GC in stats.gc. We always do this since
// it's relatively cheap and we need allocated_bytes to catch heap
@@ -606,6 +630,7 @@ stat_endGC (Capability *cap, gc_thread *initiating_gct, W_ live, W_ copied, W_ s
CAPSET_HEAP_DEFAULT,
mblocks_allocated * MBLOCK_SIZE);
}
+ RELEASE_LOCK(&stats_mutex);
}
/* -----------------------------------------------------------------------------
@@ -618,8 +643,10 @@ stat_startRP(void)
Time user, elapsed;
getProcessTimes( &user, &elapsed );
+ ACQUIRE_LOCK(&stats_mutex);
RP_start_time = user;
RPe_start_time = elapsed;
+ RELEASE_LOCK(&stats_mutex);
}
#endif /* PROFILING */
@@ -637,11 +664,14 @@ stat_endRP(
Time user, elapsed;
getProcessTimes( &user, &elapsed );
+ ACQUIRE_LOCK(&stats_mutex);
RP_tot_time += user - RP_start_time;
RPe_tot_time += elapsed - RPe_start_time;
+ double mut_time_during_RP = mut_user_time_during_RP();
+ RELEASE_LOCK(&stats_mutex);
fprintf(prof_file, "Retainer Profiling: %d, at %f seconds\n",
- retainerGeneration, mut_user_time_during_RP());
+ retainerGeneration, mut_time_during_RP);
fprintf(prof_file, "\tMax auxiliary stack size = %u\n", maxStackSize);
fprintf(prof_file, "\tAverage number of visits per object = %f\n",
averageNumVisit);
@@ -658,8 +688,10 @@ stat_startHeapCensus(void)
Time user, elapsed;
getProcessTimes( &user, &elapsed );
+ ACQUIRE_LOCK(&stats_mutex);
HC_start_time = user;
HCe_start_time = elapsed;
+ RELEASE_LOCK(&stats_mutex);
}
#endif /* PROFILING */
@@ -673,8 +705,10 @@ stat_endHeapCensus(void)
Time user, elapsed;
getProcessTimes( &user, &elapsed );
+ ACQUIRE_LOCK(&stats_mutex);
HC_tot_time += user - HC_start_time;
HCe_tot_time += elapsed - HCe_start_time;
+ RELEASE_LOCK(&stats_mutex);
}
#endif /* PROFILING */
@@ -733,7 +767,7 @@ There are currently three reporting functions:
* report_machine_readable:
Responsible for producing '+RTS -t --machine-readable' output.
* report_one_line:
- Responsible for productin '+RTS -t' output
+ Responsible for producing '+RTS -t' output
Stats are accumulated into the global variable 'stats' as the program runs, then
in 'stat_exit' we do the following:
@@ -771,10 +805,11 @@ static void free_RTSSummaryStats(RTSSummaryStats * sum)
sum->gc_summary_stats = NULL;
}
+// Must hold stats_mutex.
static void report_summary(const RTSSummaryStats* sum)
{
// We should do no calculation, other than unit changes and formatting, and
- // we should not not use any data from outside of globals, sum and stats
+ // we should not use any data from outside of globals, sum and stats
// here. See Note [RTS Stats Reporting]
uint32_t g;
@@ -997,7 +1032,7 @@ static void report_summary(const RTSSummaryStats* sum)
static void report_machine_readable (const RTSSummaryStats * sum)
{
// We should do no calculation, other than unit changes and formatting, and
- // we should not not use any data from outside of globals, sum and stats
+ // we should not use any data from outside of globals, sum and stats
// here. See Note [RTS Stats Reporting]
uint32_t g;
@@ -1153,10 +1188,11 @@ static void report_machine_readable (const RTSSummaryStats * sum)
statsPrintf(" ]\n");
}
+// Must hold stats_mutex.
static void report_one_line(const RTSSummaryStats * sum)
{
// We should do no calculation, other than unit changes and formatting, and
- // we should not not use any data from outside of globals, sum and stats
+ // we should not use any data from outside of globals, sum and stats
// here. See Note [RTS Stats Reporting]
/* print the long long separately to avoid bugginess on mingwin (2001-07-02,
@@ -1199,6 +1235,7 @@ stat_exit (void)
Time now_cpu_ns, now_elapsed_ns;
getProcessTimes(&now_cpu_ns, &now_elapsed_ns);
+ ACQUIRE_LOCK(&stats_mutex);
stats.cpu_ns = now_cpu_ns - start_init_cpu;
stats.elapsed_ns = now_elapsed_ns - start_init_elapsed;
/* avoid divide by zero if stats.total_cpu_ns is measured as 0.00
@@ -1387,6 +1424,10 @@ stat_exit (void)
report_one_line(&sum);
}
}
+ RELEASE_LOCK(&stats_mutex);
+#if defined(THREADED_RTS)
+ closeMutex(&stats_mutex);
+#endif
statsFlush();
statsClose();
@@ -1627,7 +1668,10 @@ statDescribeGens(void)
uint64_t getAllocations( void )
{
- return stats.allocated_bytes;
+ ACQUIRE_LOCK(&stats_mutex);
+ StgWord64 n = stats.allocated_bytes;
+ RELEASE_LOCK(&stats_mutex);
+ return n;
}
int getRTSStatsEnabled( void )
@@ -1640,7 +1684,9 @@ void getRTSStats( RTSStats *s )
Time current_elapsed = 0;
Time current_cpu = 0;
+ ACQUIRE_LOCK(&stats_mutex);
*s = stats;
+ RELEASE_LOCK(&stats_mutex);
getProcessTimes(¤t_cpu, ¤t_elapsed);
s->cpu_ns = current_cpu - end_init_cpu;
--
GitLab