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Fix long spinning in rtree_node_init

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rtree_node_init spinlocks the node, allocates, and then sets the node.
This is under heavy contention at the top of the tree if many threads
start to allocate at the same time.

Instead, take a per-rtree sleeping mutex to reduce spinning.  Tested
both pthreads and osx OSSpinLock, and both reduce spinning adequately

Previous benchmark time:
./ttest1 500 100
~15s

New benchmark time:
./ttest1 500 100
.57s
This commit is contained in:
Dave Watson 2016-10-31 16:23:33 -07:00 • committed by Jason Evans
parent 712fde79fd
commit 25f7bbcf28
4 changed files with 15 additions and 19 deletions
Download patch file Download diff file Expand all files Collapse all files

6
include/jemalloc/internal/rtree.h
View file

@ -23,9 +23,6 @@ typedef struct rtree_s rtree_t;
#define RTREE_HEIGHT_MAX \
((1U << (LG_SIZEOF_PTR+3)) / RTREE_BITS_PER_LEVEL)
/* Used for two-stage lock-free node initialization. */
#define RTREE_NODE_INITIALIZING ((rtree_elm_t *)0x1)
#define RTREE_CTX_INITIALIZER { \
false, \
0, \
@ -139,6 +136,7 @@ struct rtree_s {
*/
unsigned start_level[RTREE_HEIGHT_MAX + 1];
rtree_level_t levels[RTREE_HEIGHT_MAX];
malloc_mutex_t init_lock;
};
#endif /* JEMALLOC_H_STRUCTS */
@ -251,7 +249,7 @@ JEMALLOC_ALWAYS_INLINE bool
rtree_node_valid(rtree_elm_t *node)
{
return ((uintptr_t)node > (uintptr_t)RTREE_NODE_INITIALIZING);
return ((uintptr_t)node != (uintptr_t)0);
}
JEMALLOC_ALWAYS_INLINE rtree_elm_t *