be8e59f5a6
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. |
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jemalloc | ||
msvc_compat |