Tcache: make slot sizing configurable.
This commit is contained in:
committed by
David Goldblatt
parent
b58dea8d1b
commit
181093173d
@@ -1379,6 +1379,16 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
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*/
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CONF_HANDLE_SSIZE_T(opt_lg_tcache_nslots_mul,
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"lg_tcache_nslots_mul", -16, 16)
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/* Ditto with values past 2048. */
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CONF_HANDLE_UNSIGNED(opt_tcache_nslots_small_min,
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"tcache_nslots_small_min", 1, 2048,
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CONF_CHECK_MIN, CONF_CHECK_MAX, /* clip */ true)
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CONF_HANDLE_UNSIGNED(opt_tcache_nslots_small_max,
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"tcache_nslots_small_max", 1, 2048,
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CONF_CHECK_MIN, CONF_CHECK_MAX, /* clip */ true)
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CONF_HANDLE_UNSIGNED(opt_tcache_nslots_large,
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"tcache_nslots_large", 1, 2048,
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CONF_CHECK_MIN, CONF_CHECK_MAX, /* clip */ true)
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/*
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* The runtime option of oversize_threshold remains
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49
src/tcache.c
49
src/tcache.c
@@ -10,8 +10,13 @@
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/******************************************************************************/
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/* Data. */
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bool opt_tcache = true;
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ssize_t opt_lg_tcache_max = LG_TCACHE_MAXCLASS_DEFAULT;
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bool opt_tcache = true;
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ssize_t opt_lg_tcache_max = LG_TCACHE_MAXCLASS_DEFAULT;
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/* Reasonable defaults for min and max values. */
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unsigned opt_tcache_nslots_small_min = 20;
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unsigned opt_tcache_nslots_small_max = 200;
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unsigned opt_tcache_nslots_large = 20;
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/*
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* We attempt to make the number of slots in a tcache bin for a given size class
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@@ -19,7 +24,7 @@ ssize_t opt_lg_tcache_max = LG_TCACHE_MAXCLASS_DEFAULT;
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* the multiplier is 1/2 (i.e. we set the maximum number of objects in the
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* tcache to half the number of objects in a slab).
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* This is bounded by some other constraints as well, like the fact that it
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* must be even, must be less than TCACHE_NSLOTS_SMALL_MAX, etc..
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* must be even, must be less than opt_tcache_nslots_small_max, etc..
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*/
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ssize_t opt_lg_tcache_nslots_mul = -1;
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@@ -485,7 +490,6 @@ tcache_init(tsd_t *tsd, tcache_slow_t *tcache_slow, tcache_t *tcache,
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tcache_slow->arena = NULL;
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tcache_slow->dyn_alloc = mem;
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assert((TCACHE_NSLOTS_SMALL_MAX & 1U) == 0);
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memset(tcache->bins, 0, sizeof(cache_bin_t) * nhbins);
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size_t cur_offset = 0;
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@@ -792,10 +796,37 @@ static unsigned
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tcache_ncached_max_compute(szind_t szind) {
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if (szind >= SC_NBINS) {
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assert(szind < nhbins);
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return TCACHE_NSLOTS_LARGE;
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return opt_tcache_nslots_large;
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}
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unsigned slab_nregs = bin_infos[szind].nregs;
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/* We may modify these values; start with the opt versions. */
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unsigned nslots_small_min = opt_tcache_nslots_small_min;
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unsigned nslots_small_max = opt_tcache_nslots_small_max;
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/*
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* Clamp values to meet our constraints -- even, nonzero, min < max, and
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* suitable for a cache bin size.
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*/
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if (opt_tcache_nslots_small_max > CACHE_BIN_NCACHED_MAX) {
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nslots_small_max = CACHE_BIN_NCACHED_MAX;
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}
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if (nslots_small_min % 2 != 0) {
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nslots_small_min++;
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}
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if (nslots_small_max % 2 != 0) {
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nslots_small_max--;
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}
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if (nslots_small_min < 2) {
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nslots_small_min = 2;
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}
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if (nslots_small_max < 2) {
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nslots_small_max = 2;
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}
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if (nslots_small_min > nslots_small_max) {
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nslots_small_min = nslots_small_max;
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}
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unsigned candidate;
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if (opt_lg_tcache_nslots_mul < 0) {
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candidate = slab_nregs >> (-opt_lg_tcache_nslots_mul);
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@@ -810,12 +841,12 @@ tcache_ncached_max_compute(szind_t szind) {
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*/
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++candidate;
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}
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if (candidate <= TCACHE_NSLOTS_SMALL_MIN) {
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return TCACHE_NSLOTS_SMALL_MIN;
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} else if (candidate <= TCACHE_NSLOTS_SMALL_MAX) {
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if (candidate <= nslots_small_min) {
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return nslots_small_min;
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} else if (candidate <= nslots_small_max) {
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return candidate;
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} else {
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return TCACHE_NSLOTS_SMALL_MAX;
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return nslots_small_max;
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}
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}
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