bpo-37729: gc: write stats at once (GH-15050)

gc used several PySys_WriteStderr() calls to write stats.
It caused stats mixed up when stderr is shared by multiple
processes like this:

  gc: collecting generation 2...
  gc: objects in each generation: 0 0gc: collecting generation 2...
  gc: objects in each generation: 0 0 126077 126077
  gc: objects in permanent generation: 0

  gc: objects in permanent generation: 0
  gc: done, 112575 unreachable, 0 uncollectablegc: done, 112575 unreachable, 0 uncollectable, 0.2223s elapsed
  , 0.2344s elapsed
(cherry picked from commit bf8162c8c4)

Co-authored-by: Inada Naoki <songofacandy@gmail.com>
This commit is contained in:
Miss Islington (bot) 2019-08-05 00:20:25 -07:00 committed by Inada Naoki
parent 5349f8cd78
commit e8ea34855c
1 changed files with 25 additions and 20 deletions

View File

@ -962,6 +962,25 @@ clear_freelists(void)
(void)PyContext_ClearFreeList();
}
// Show stats for objects in each gennerations.
static void
show_stats_each_generations(struct _gc_runtime_state *state)
{
char buf[100];
size_t pos = 0;
for (int i = 0; i < NUM_GENERATIONS && pos < sizeof(buf); i++) {
pos += PyOS_snprintf(buf+pos, sizeof(buf)-pos,
" %"PY_FORMAT_SIZE_T"d",
gc_list_size(GEN_HEAD(state, i)));
}
PySys_FormatStderr(
"gc: objects in each generation:%s\n"
"gc: objects in permanent generation: %zd\n",
buf, gc_list_size(&state->permanent_generation.head));
}
/* This is the main function. Read this to understand how the
* collection process works. */
static Py_ssize_t
@ -979,17 +998,9 @@ collect(struct _gc_runtime_state *state, int generation,
_PyTime_t t1 = 0; /* initialize to prevent a compiler warning */
if (state->debug & DEBUG_STATS) {
PySys_WriteStderr("gc: collecting generation %d...\n",
generation);
PySys_WriteStderr("gc: objects in each generation:");
for (i = 0; i < NUM_GENERATIONS; i++)
PySys_FormatStderr(" %zd",
gc_list_size(GEN_HEAD(state, i)));
PySys_WriteStderr("\ngc: objects in permanent generation: %zd",
gc_list_size(&state->permanent_generation.head));
PySys_WriteStderr("gc: collecting generation %d...\n", generation);
show_stats_each_generations(state);
t1 = _PyTime_GetMonotonicClock();
PySys_WriteStderr("\n");
}
if (PyDTrace_GC_START_ENABLED())
@ -1103,16 +1114,10 @@ collect(struct _gc_runtime_state *state, int generation,
debug_cycle("uncollectable", FROM_GC(gc));
}
if (state->debug & DEBUG_STATS) {
_PyTime_t t2 = _PyTime_GetMonotonicClock();
if (m == 0 && n == 0)
PySys_WriteStderr("gc: done");
else
PySys_FormatStderr(
"gc: done, %zd unreachable, %zd uncollectable",
n+m, n);
PySys_WriteStderr(", %.4fs elapsed\n",
_PyTime_AsSecondsDouble(t2 - t1));
double d = _PyTime_AsSecondsDouble(_PyTime_GetMonotonicClock() - t1);
PySys_FormatStderr(
"gc: done, %zd unreachable, %zd uncollectable, %.4fs elapsed\n",
n+m, n, d);
}
/* Append instances in the uncollectable set to a Python