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| author | Ben Maurer <bmaurer@fb.com> | 2014-04-05 22:59:08 (GMT) |
|---|---|---|
| committer | Ben Maurer <bmaurer@fb.com> | 2014-04-05 22:59:08 (GMT) |
| commit | be8e59f5a64ef775c9694aee0d6a87d92336d303 (patch) | |
| tree | daf932cc9677842166eed330559acbef1000d27e /src/jemalloc.c | |
| parent | 46c0af68bd248b04df75e4f92d5fb804c3d75340 (diff) | |
| download | jemalloc-be8e59f5a64ef775c9694aee0d6a87d92336d303.zip jemalloc-be8e59f5a64ef775c9694aee0d6a87d92336d303.tar.gz jemalloc-be8e59f5a64ef775c9694aee0d6a87d92336d303.tar.bz2 | |
Don't dereference chunk->arena in free() hot path
When you call free() we load chunk->arena even though that
data isn't used on the tcache hot path.
In profiling some FB applications, I found that ~30% of the
dTLB misses in the free() function come from this line. With
4 MB chunks, the arena_chunk_t->map is ~ 32 KB (1024 pages
in the chunk, 4 8 byte pointers in arena_chunk_map_t). This
means there's only a 1/8 chance of the page containing
chunk->arena also comtaining the map bits.
Diffstat (limited to 'src/jemalloc.c')
| -rw-r--r-- | src/jemalloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/jemalloc.c b/src/jemalloc.c index 204778b..558dbb2 100644 --- a/src/jemalloc.c +++ b/src/jemalloc.c @@ -2103,7 +2103,7 @@ a0free(void *ptr) chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr); if (chunk != ptr) - arena_dalloc(chunk->arena, chunk, ptr, false); + arena_dalloc(chunk, ptr, false); else huge_dalloc(ptr, true); } |