Add/use adaptive spinning.

Add spin_t and spin_{init,adaptive}(), which provide a simple
abstraction for adaptive spinning.

Adaptively spin during busy waits in bootstrapping and rtree node
initialization.
This commit is contained in:
Jason Evans 2016-10-13 14:47:50 -07:00
parent a2539fab95
commit 9737685943
6 changed files with 66 additions and 2 deletions

View File

@ -101,6 +101,7 @@ C_SRCS := $(srcroot)src/jemalloc.c \
$(srcroot)src/quarantine.c \
$(srcroot)src/rtree.c \
$(srcroot)src/stats.c \
$(srcroot)src/spin.c \
$(srcroot)src/tcache.c \
$(srcroot)src/ticker.c \
$(srcroot)src/tsd.c \

View File

@ -369,6 +369,7 @@ typedef unsigned szind_t;
#include "jemalloc/internal/valgrind.h"
#include "jemalloc/internal/util.h"
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/spin.h"
#include "jemalloc/internal/prng.h"
#include "jemalloc/internal/ticker.h"
#include "jemalloc/internal/ckh.h"
@ -401,6 +402,7 @@ typedef unsigned szind_t;
#include "jemalloc/internal/valgrind.h"
#include "jemalloc/internal/util.h"
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/spin.h"
#include "jemalloc/internal/prng.h"
#include "jemalloc/internal/ticker.h"
#include "jemalloc/internal/ckh.h"
@ -502,6 +504,7 @@ void jemalloc_postfork_child(void);
#include "jemalloc/internal/valgrind.h"
#include "jemalloc/internal/util.h"
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/spin.h"
#include "jemalloc/internal/prng.h"
#include "jemalloc/internal/ticker.h"
#include "jemalloc/internal/ckh.h"
@ -534,6 +537,7 @@ void jemalloc_postfork_child(void);
#include "jemalloc/internal/valgrind.h"
#include "jemalloc/internal/util.h"
#include "jemalloc/internal/atomic.h"
#include "jemalloc/internal/spin.h"
#include "jemalloc/internal/prng.h"
#include "jemalloc/internal/ticker.h"
#include "jemalloc/internal/ckh.h"

View File

@ -0,0 +1,51 @@
/******************************************************************************/
#ifdef JEMALLOC_H_TYPES
typedef struct spin_s spin_t;
#endif /* JEMALLOC_H_TYPES */
/******************************************************************************/
#ifdef JEMALLOC_H_STRUCTS
struct spin_s {
unsigned iteration;
};
#endif /* JEMALLOC_H_STRUCTS */
/******************************************************************************/
#ifdef JEMALLOC_H_EXTERNS
#endif /* JEMALLOC_H_EXTERNS */
/******************************************************************************/
#ifdef JEMALLOC_H_INLINES
#ifndef JEMALLOC_ENABLE_INLINE
void spin_init(spin_t *spin);
void spin_adaptive(spin_t *spin);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_SPIN_C_))
JEMALLOC_INLINE void
spin_init(spin_t *spin)
{
spin->iteration = 0;
}
JEMALLOC_INLINE void
spin_adaptive(spin_t *spin)
{
volatile uint64_t i;
for (i = 0; i < (KQU(1) << spin->iteration); i++)
CPU_SPINWAIT;
if (spin->iteration < 63)
spin->iteration++;
}
#endif
#endif /* JEMALLOC_H_INLINES */
/******************************************************************************/

View File

@ -1283,10 +1283,13 @@ malloc_init_hard_needed(void)
}
#ifdef JEMALLOC_THREADED_INIT
if (malloc_initializer != NO_INITIALIZER && !IS_INITIALIZER) {
spin_t spinner;
/* Busy-wait until the initializing thread completes. */
spin_init(&spinner);
do {
malloc_mutex_unlock(TSDN_NULL, &init_lock);
CPU_SPINWAIT;
spin_adaptive(&spinner);
malloc_mutex_lock(TSDN_NULL, &init_lock);
} while (!malloc_initialized());
return (false);

View File

@ -96,12 +96,15 @@ rtree_node_init(rtree_t *rtree, unsigned level, rtree_node_elm_t **elmp)
rtree_node_elm_t *node;
if (atomic_cas_p((void **)elmp, NULL, RTREE_NODE_INITIALIZING)) {
spin_t spinner;
/*
* Another thread is already in the process of initializing.
* Spin-wait until initialization is complete.
*/
spin_init(&spinner);
do {
CPU_SPINWAIT;
spin_adaptive(&spinner);
node = atomic_read_p((void **)elmp);
} while (node == RTREE_NODE_INITIALIZING);
} else {

2
src/spin.c Normal file
View File

@ -0,0 +1,2 @@
#define JEMALLOC_SPIN_C_
#include "jemalloc/internal/jemalloc_internal.h"