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optimize mi_bin

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This commit is contained in:
daanx 2025-02-11 14:27:01 -08:00
parent d3897635ad
commit c62d276835
2 changed files with 43 additions and 42 deletions
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39
src/page-queue.c
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@ -58,26 +58,22 @@ static inline bool mi_page_queue_is_special(const mi_page_queue_t* pq) {
// We use `wsize` for the size in "machine word sizes",
// i.e. byte size == `wsize*sizeof(void*)`.
static inline uint8_t mi_bin(size_t size) {
size_t wsize = _mi_wsize_from_size(size);
uint8_t bin;
if (wsize <= 1) {
bin = 1;
size_t wsize = _mi_wsize_from_size(size);
#if defined(MI_ALIGN4W)
if mi_likely(wsize <= 4) {
return (wsize <= 1 ? 1 : (wsize+1)&~1); // round to double word sizes
}
#if defined(MI_ALIGN4W)
else if (wsize <= 4) {
bin = (uint8_t)((wsize+1)&~1); // round to double word sizes
#elif defined(MI_ALIGN2W)
if mi_likely(wsize <= 8) {
return (wsize <= 1 ? 1 : (wsize+1)&~1); // round to double word sizes
}
#elif defined(MI_ALIGN2W)
else if (wsize <= 8) {
bin = (uint8_t)((wsize+1)&~1); // round to double word sizes
#else
if mi_likely(wsize <= 8) {
return (wsize == 0 ? 1 : wsize);
}
#else
else if (wsize <= 8) {
bin = (uint8_t)wsize;
}
#endif
else if (wsize > MI_LARGE_OBJ_WSIZE_MAX) {
bin = MI_BIN_HUGE;
#endif
else if mi_unlikely(wsize > MI_LARGE_OBJ_WSIZE_MAX) {
return MI_BIN_HUGE;
}
else {
#if defined(MI_ALIGN4W)
@ -85,15 +81,14 @@ static inline uint8_t mi_bin(size_t size) {
#endif
wsize--;
// find the highest bit
uint8_t b = (uint8_t)mi_bsr(wsize); // note: wsize != 0
const size_t b = mi_bsr(wsize); // note: wsize != 0
// and use the top 3 bits to determine the bin (~12.5% worst internal fragmentation).
// - adjust with 3 because we use do not round the first 8 sizes
// which each get an exact bin
bin = ((b << 2) + (uint8_t)((wsize >> (b - 2)) & 0x03)) - 3;
mi_assert_internal(bin < MI_BIN_HUGE);
const size_t bin = ((b << 2) + ((wsize >> (b - 2)) & 0x03)) - 3;
mi_assert_internal(bin > 0 && bin < MI_BIN_HUGE);
return bin;
}
mi_assert_internal(bin > 0 && bin <= MI_BIN_HUGE);
return bin;
}