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Use pairing heap for arena->runs_avail

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Use pairing heap instead of red black tree in arena runs_avail.  The
extra links are unioned with the bitmap_t, so this change doesn't use
any extra memory.

Canaries show this change to be a 1% cpu win, and 2% latency win.  In
particular, large free()s, and small bin frees are now O(1) (barring
coalescing).

I also tested changing bin->runs to be a pairing heap, but saw a much
smaller win, and it would mean increasing the size of arena_run_s by two
pointers, so I left that as an rb-tree for now.
This commit is contained in:
Dave Watson
2016-02-29 11:54:42 -08:00
committed by Jason Evans
parent f8d80d62a8
commit 4a0dbb5ac8
3 changed files with 40 additions and 18 deletions
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29
include/jemalloc/internal/arena.h
View File

@@ -36,6 +36,7 @@ typedef enum {
#define DECAY_NTICKS_PER_UPDATE 1000
typedef struct arena_runs_dirty_link_s arena_runs_dirty_link_t;
typedef struct arena_avail_links_s arena_avail_links_t;
typedef struct arena_run_s arena_run_t;
typedef struct arena_chunk_map_bits_s arena_chunk_map_bits_t;
typedef struct arena_chunk_map_misc_s arena_chunk_map_misc_t;
@@ -146,6 +147,11 @@ struct arena_runs_dirty_link_s {
qr(arena_runs_dirty_link_t) rd_link;
};
struct arena_avail_links_s {
arena_runs_dirty_link_t rd;
ph_node_t ph_link;
};
/*
* Each arena_chunk_map_misc_t corresponds to one page within the chunk, just
* like arena_chunk_map_bits_t. Two separate arrays are stored within each
@@ -163,7 +169,7 @@ struct arena_chunk_map_misc_s {
union {
/* Linkage for list of dirty runs. */
arena_runs_dirty_link_t rd;
arena_avail_links_t avail;
/* Profile counters, used for large object runs. */
union {
@@ -457,10 +463,10 @@ struct arena_s {
arena_bin_t bins[NBINS];
/*
* Quantized address-ordered trees of this arena's available runs. The
* trees are used for first-best-fit run allocation.
* Quantized address-ordered heaps of this arena's available runs. The
* heaps are used for first-best-fit run allocation.
*/
arena_run_tree_t runs_avail[1]; /* Dynamically sized. */
ph_heap_t runs_avail[1]; /* Dynamically sized. */
};
/* Used in conjunction with tsd for fast arena-related context lookup. */
@@ -600,6 +606,7 @@ arena_chunk_map_misc_t *arena_miscelm_get(arena_chunk_t *chunk,
size_t arena_miscelm_to_pageind(const arena_chunk_map_misc_t *miscelm);
void *arena_miscelm_to_rpages(arena_chunk_map_misc_t *miscelm);
arena_chunk_map_misc_t *arena_rd_to_miscelm(arena_runs_dirty_link_t *rd);
arena_chunk_map_misc_t *arena_ph_to_miscelm(ph_node_t *ph);
arena_chunk_map_misc_t *arena_run_to_miscelm(arena_run_t *run);
size_t *arena_mapbitsp_get(arena_chunk_t *chunk, size_t pageind);
size_t arena_mapbitsp_read(size_t *mapbitsp);
@@ -702,7 +709,19 @@ JEMALLOC_ALWAYS_INLINE arena_chunk_map_misc_t *
arena_rd_to_miscelm(arena_runs_dirty_link_t *rd)
{
arena_chunk_map_misc_t *miscelm = (arena_chunk_map_misc_t
*)((uintptr_t)rd - offsetof(arena_chunk_map_misc_t, rd));
*)((uintptr_t)rd - offsetof(arena_chunk_map_misc_t, avail));
assert(arena_miscelm_to_pageind(miscelm) >= map_bias);
assert(arena_miscelm_to_pageind(miscelm) < chunk_npages);
return (miscelm);
}
JEMALLOC_ALWAYS_INLINE arena_chunk_map_misc_t *
arena_ph_to_miscelm(ph_node_t *ph)
{
arena_chunk_map_misc_t *miscelm = (arena_chunk_map_misc_t *)
((uintptr_t)ph - offsetof(arena_chunk_map_misc_t, avail.ph_link));
assert(arena_miscelm_to_pageind(miscelm) >= map_bias);
assert(arena_miscelm_to_pageind(miscelm) < chunk_npages);

1
include/jemalloc/internal/private_symbols.txt
View File

@@ -79,6 +79,7 @@ arena_nthreads_dec
arena_nthreads_get
arena_nthreads_inc
arena_palloc
arena_ph_to_miscelm
arena_postfork_child
arena_postfork_parent
arena_prefork