Author: Armin Rigo <[email protected]>
Branch:
Changeset: r1883:c8ccc22dbf16
Date: 2015-06-24 16:31 +0200
http://bitbucket.org/pypy/stmgc/changeset/c8ccc22dbf16/
Log: Try to be a bit more careful in prof.c
diff --git a/c8/stm/prof.c b/c8/stm/prof.c
--- a/c8/stm/prof.c
+++ b/c8/stm/prof.c
@@ -2,7 +2,7 @@
#include <time.h>
-static FILE *profiling_file;
+static FILE *volatile profiling_file;
static char *profiling_basefn = NULL;
static stm_expand_marker_fn profiling_expand_marker;
@@ -26,9 +26,6 @@
struct buf_s buf;
struct timespec t;
- clock_gettime(CLOCK_MONOTONIC, &t);
- buf.tv_sec = t.tv_sec;
- buf.tv_nsec = t.tv_nsec;
buf.thread_num = tl->thread_local_counter;
buf.event = event;
buf.marker_length = 0;
@@ -39,10 +36,29 @@
buf.extra, MARKER_LEN_MAX);
}
- if (fwrite(&buf, offsetof(struct buf_s, extra) + buf.marker_length,
- 1, profiling_file) != 1) {
+ size_t result, outsize = offsetof(struct buf_s, extra) + buf.marker_length;
+ FILE *f = profiling_file;
+ if (f == NULL)
+ return;
+ flockfile(f);
+
+ /* We expect the following CLOCK_MONOTONIC to be really monotonic:
+ it should guarantee that the file will be perfectly ordered by time.
+ That's why we do it inside flockfile()/funlockfile(). */
+ clock_gettime(CLOCK_MONOTONIC, &t);
+ buf.tv_sec = t.tv_sec;
+ buf.tv_nsec = t.tv_nsec;
+
+ result = fwrite_unlocked(&buf, outsize, 1, f);
+ funlockfile(f);
+
+ if (result != 1) {
fprintf(stderr, "stmgc: profiling log file closed unexpectedly: %m\n");
- close_timing_log();
+
+ /* xxx the FILE leaks here, but it is better than random crashes if
+ we try to close it while other threads are still writing to it
+ */
+ profiling_file = NULL;
}
}
@@ -54,11 +70,12 @@
static bool open_timing_log(const char *filename)
{
- profiling_file = fopen(filename, "w");
- if (profiling_file == NULL)
+ FILE *f = fopen(filename, "w");
+ profiling_file = f;
+ if (f == NULL)
return false;
- fwrite("STMGC-C8-PROF01\n", 16, 1, profiling_file);
+ fwrite("STMGC-C8-PROF01\n", 16, 1, f);
stmcb_timing_event = _stm_profiling_event;
return true;
}
@@ -66,9 +83,11 @@
static bool close_timing_log(void)
{
if (stmcb_timing_event == &_stm_profiling_event) {
+ FILE *f = profiling_file;
stmcb_timing_event = NULL;
- fclose(profiling_file);
profiling_file = NULL;
+ if (f != NULL)
+ fclose(f);
return true;
}
return false;
@@ -76,8 +95,9 @@
static void prof_forksupport_prepare(void)
{
- if (profiling_file != NULL)
- fflush(profiling_file);
+ FILE *f = profiling_file;
+ if (f != NULL)
+ fflush(f);
}
static void prof_forksupport_child(void)
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