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fc615739cb
This adds a fast-path for threads freeing a small number of allocations to bins which are not their "home-base" and which encounter lock contention in attempting to do so. In producer-consumer workflows, such small lock hold times can cause lock convoying that greatly increases overall bin mutex contention.
55 lines
2.0 KiB
C
55 lines
2.0 KiB
C
#include "jemalloc/internal/jemalloc_preamble.h"
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#include "jemalloc/internal/jemalloc_internal_includes.h"
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#include "jemalloc/internal/bin_info.h"
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/*
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* We leave bin-batching disabled by default, with other settings chosen mostly
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* empirically; across the test programs I looked at they provided the most bang
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* for the buck. With other default settings, these choices for bin batching
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* result in them consuming far less memory (even in the worst case) than the
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* tcaches themselves, the arena, etc.
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* Note that we always try to pop all bins on every arena cache bin lock
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* operation, so the typical memory waste is far less than this (and only on
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* hot bins, which tend to be large anyways).
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*/
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size_t opt_bin_info_max_batched_size = 0; /* 192 is a good default. */
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size_t opt_bin_info_remote_free_max_batch = 4;
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size_t opt_bin_info_remote_free_max = BIN_REMOTE_FREE_ELEMS_MAX;
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bin_info_t bin_infos[SC_NBINS];
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szind_t bin_info_nbatched_sizes;
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unsigned bin_info_nbatched_bins;
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unsigned bin_info_nunbatched_bins;
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static void
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bin_infos_init(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
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bin_info_t infos[SC_NBINS]) {
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for (unsigned i = 0; i < SC_NBINS; i++) {
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bin_info_t *bin_info = &infos[i];
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sc_t *sc = &sc_data->sc[i];
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bin_info->reg_size = ((size_t)1U << sc->lg_base)
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+ ((size_t)sc->ndelta << sc->lg_delta);
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bin_info->slab_size = (sc->pgs << LG_PAGE);
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bin_info->nregs =
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(uint32_t)(bin_info->slab_size / bin_info->reg_size);
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bin_info->n_shards = bin_shard_sizes[i];
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bitmap_info_t bitmap_info = BITMAP_INFO_INITIALIZER(
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bin_info->nregs);
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bin_info->bitmap_info = bitmap_info;
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if (bin_info->reg_size <= opt_bin_info_max_batched_size) {
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bin_info_nbatched_sizes++;
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bin_info_nbatched_bins += bin_info->n_shards;
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} else {
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bin_info_nunbatched_bins += bin_info->n_shards;
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}
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}
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}
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void
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bin_info_boot(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS]) {
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assert(sc_data->initialized);
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bin_infos_init(sc_data, bin_shard_sizes, bin_infos);
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}
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