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mpool: ldiv() division bites the dust in favor of some bitops

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before:
 1,747,160,336  PROGRAM TOTALS
after:
 1,371,806,087  PROGRAM TOTALS
This commit is contained in:
Christian Thaeter 2009-05-14 23:48:39 +02:00
parent 9ed817df97
commit 0dc0d18703
1 changed files with 40 additions and 47 deletions
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87
src/lib/mpool.c
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@ -26,6 +26,14 @@
#include "mpool.h"
#if UINTPTR_MAX > 4294967295U /* 64 bit */
#define MPOOL_DIV_SHIFT 6
#else /* 32 bit */
#define MPOOL_DIV_SHIFT 5
#endif
/*
Cluster and node structures are private
*/
@ -99,10 +107,11 @@ bitmap_bit_get_nth (MPoolcluster cluster, unsigned index)
{
TRACE (mpool_dbg, "cluster %p: index %u", cluster, index);
ldiv_t div = ldiv(index, sizeof(uintptr_t)*CHAR_BIT);
uintptr_t quot = index>>MPOOL_DIV_SHIFT;
uintptr_t rem = index & ~((~0ULL)<<MPOOL_DIV_SHIFT);
uintptr_t* bitmap = (uintptr_t*)&cluster->data;
return bitmap[div.quot] & ((uintptr_t)1<<div.rem);
return bitmap[quot] & ((uintptr_t)1<<rem);
}
@ -221,31 +230,27 @@ alloc_near (MPoolcluster cluster, MPool self, void* locality)
MPOOL_BITMAP_SIZE (((MPool)self)->elements_per_cluster); /* bitmap */
uintptr_t index = (locality - begin_of_elements) / self->elem_size;
#if UINTPTR_MAX > 4294967295U /* 64 bit */
lldiv_t div = lldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#else /* 32 bit */
ldiv_t div = ldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#endif
uintptr_t quot = index>>MPOOL_DIV_SHIFT;
uintptr_t rem = index & ~((~0ULL)<<MPOOL_DIV_SHIFT);
uintptr_t* bitmap = (uintptr_t*)&cluster->data;
unsigned r = ~0U;
/* the bitmap word at locality */
if (bitmap[div.quot] < UINTPTR_MAX)
if (bitmap[quot] < UINTPTR_MAX)
{
r = uintptr_nearestbit (~bitmap[div.quot], div.rem);
r = uintptr_nearestbit (~bitmap[quot], rem);
}
/* the bitmap word before locality, this gives a slight bias towards the begin, keeping the pool compact */
else if (div.quot && bitmap[div.quot-1] < UINTPTR_MAX)
else if (quot && bitmap[quot-1] < UINTPTR_MAX)
{
--div.quot;
r = uintptr_nearestbit (~bitmap[div.quot], sizeof(uintptr_t)*CHAR_BIT-1);
--quot;
r = uintptr_nearestbit (~bitmap[quot], sizeof(uintptr_t)*CHAR_BIT-1);
}
if (r != ~0U && (div.quot*sizeof(uintptr_t)*CHAR_BIT+r) < self->elements_per_cluster)
if (r != ~0U && (quot*sizeof(uintptr_t)*CHAR_BIT+r) < self->elements_per_cluster)
{
void* ret = begin_of_elements + ((uintptr_t)(div.quot*sizeof(uintptr_t)*CHAR_BIT+r)*self->elem_size);
void* ret = begin_of_elements + ((uintptr_t)(quot*sizeof(uintptr_t)*CHAR_BIT+r)*self->elem_size);
return ret;
}
return NULL;
@ -261,17 +266,13 @@ bitmap_set_element (MPoolcluster cluster, MPool self, void* element)
MPOOL_BITMAP_SIZE (((MPool)self)->elements_per_cluster); /* bitmap */
uintptr_t index = (element - begin_of_elements) / self->elem_size;
#if UINTPTR_MAX > 4294967295U /* 64 bit */
lldiv_t div = lldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#else /* 32 bit */
ldiv_t div = ldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#endif
uintptr_t quot = index>>MPOOL_DIV_SHIFT;
uintptr_t rem = index & ~((~0ULL)<<MPOOL_DIV_SHIFT);
uintptr_t* bitmap = (uintptr_t*)&cluster->data;
bitmap[div.quot] |= ((uintptr_t)1<<div.rem);
bitmap[quot] |= ((uintptr_t)1<<rem);
TRACE (mpool_dbg, "set bit %d, index %d, of %p is %p", div.rem, div.quot, element, bitmap[div.quot]);
TRACE (mpool_dbg, "set bit %d, index %d, of %p is %p", rem, quot, element, bitmap[quot]);
}
@ -284,17 +285,13 @@ bitmap_clear_element (MPoolcluster cluster, MPool self, void* element)
MPOOL_BITMAP_SIZE (((MPool)self)->elements_per_cluster); /* bitmap */
uintptr_t index = (element - begin_of_elements) / self->elem_size;
#if UINTPTR_MAX > 4294967295U /* 64 bit */
lldiv_t div = lldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#else /* 32 bit */
ldiv_t div = ldiv(index, sizeof(uintptr_t)*CHAR_BIT);
#endif
uintptr_t quot = index>>MPOOL_DIV_SHIFT;
uintptr_t rem = index & ~((~0ULL)<<MPOOL_DIV_SHIFT);
uintptr_t* bitmap = (uintptr_t*)&cluster->data;
bitmap[div.quot] &= ~((uintptr_t)1<<div.rem);
bitmap[quot] &= ~((uintptr_t)1<<rem);
TRACE (mpool_dbg, "cleared bit %d, index %d, of %p is %p", div.rem, div.quot, element, bitmap[div.quot]);
TRACE (mpool_dbg, "cleared bit %d, index %d, of %p is %p", rem, quot, element, bitmap[quot]);
}
@ -352,36 +349,32 @@ find_near (MPoolcluster cluster, MPool self, void* element)
MPOOL_BITMAP_SIZE (((MPool)self)->elements_per_cluster); /* bitmap */
uintptr_t index = (element - begin_of_elements) / self->elem_size;
#if UINTPTR_MAX > 4294967295U /* 64 bit */
lldiv_t div = lldiv (index, sizeof(uintptr_t)*CHAR_BIT);
#else /* 32 bit */
ldiv_t div = ldiv (index, sizeof(uintptr_t)*CHAR_BIT);
#endif
uintptr_t quot = index>>MPOOL_DIV_SHIFT;
uintptr_t rem = index & ~((~0ULL)<<MPOOL_DIV_SHIFT);
uintptr_t* bitmap = (uintptr_t*)&cluster->data;
unsigned r = ~0U;
/* the bitmap word at locality */
if (bitmap[div.quot] < UINTPTR_MAX)
if (bitmap[quot] < UINTPTR_MAX)
{
r = uintptr_nearestbit (~bitmap[div.quot], div.rem);
r = uintptr_nearestbit (~bitmap[quot], rem);
}
/* the bitmap word after element, we assume that elements after the searched element are more likely be free */
else if (index < self->elements_per_cluster && bitmap[div.quot+1] < UINTPTR_MAX)
else if (index < self->elements_per_cluster && bitmap[quot+1] < UINTPTR_MAX)
{
++div.quot;
r = uintptr_nearestbit (~bitmap[div.quot], 0);
++quot;
r = uintptr_nearestbit (~bitmap[quot], 0);
}
/* finally the bitmap word before element */
else if (index > 0 && bitmap[div.quot-1] < UINTPTR_MAX)
else if (index > 0 && bitmap[quot-1] < UINTPTR_MAX)
{
--div.quot;
r = uintptr_nearestbit (~bitmap[div.quot], sizeof(uintptr_t)*CHAR_BIT-1);
--quot;
r = uintptr_nearestbit (~bitmap[quot], sizeof(uintptr_t)*CHAR_BIT-1);
}
if (r != ~0U && (div.quot*sizeof(uintptr_t)*CHAR_BIT+r) < self->elements_per_cluster)
return begin_of_elements + ((uintptr_t)(div.quot*sizeof(uintptr_t)*CHAR_BIT+r)*self->elem_size);
if (r != ~0U && (quot*sizeof(uintptr_t)*CHAR_BIT+r) < self->elements_per_cluster)
return begin_of_elements + ((uintptr_t)(quot*sizeof(uintptr_t)*CHAR_BIT+r)*self->elem_size);
return NULL;
}