suzanne.soy/racket
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drop an unnecesary lock

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The recent addition of a shared table of names for shared code
caused bad performance on some machines (such as Robby's)
due to the lock on the table. The lock dosn't seem to be necessary
for platforms where places are supported, though.
This commit is contained in:
Matthew Flatt 2011-09-14 14:28:19 -06:00
parent bbb38c0ff9
commit 7315bfa554
1 changed files with 4 additions and 16 deletions
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20
src/racket/src/codetab.inc
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@ -22,9 +22,12 @@ extern MZ_DLLIMPORT int GC_is_marked(void *);
THREAD_LOCAL_DECL(static void **codetab_tree); THREAD_LOCAL_DECL(static void **codetab_tree);
THREAD_LOCAL_DECL(static int during_set); THREAD_LOCAL_DECL(static int during_set);
#ifdef MZ_USE_PLACES #ifdef MZ_USE_PLACES
/* This table is shared but not locked; we rely on x86-TSO
and the fact that entries are only added (never removed)
to skip the lock: */
static void **shared_codetab_tree; static void **shared_codetab_tree;
static mzrt_rwlock *shared_codetab_lock;
#endif #endif
static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing); static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing);
@ -60,9 +63,7 @@ static void *find_symbol(uintptr_t v)
#ifdef MZ_USE_PLACES #ifdef MZ_USE_PLACES
if (!r && shared_codetab_tree) { if (!r && shared_codetab_tree) {
mzrt_rwlock_rdlock(shared_codetab_lock);
r = do_find_symbol(shared_codetab_tree, v); r = do_find_symbol(shared_codetab_tree, v);
mzrt_rwlock_unlock(shared_codetab_lock);
} }
#endif #endif
@ -99,13 +100,6 @@ void scheme_jit_add_symbol(uintptr_t start, uintptr_t end, void *value, int gc_a
#ifdef MZ_USE_PLACES #ifdef MZ_USE_PLACES
if (!gc_able) { if (!gc_able) {
if (!shared_codetab_lock) {
/* this function will be called in the main place
before others are started, so a lazy lock creation
is ok */
mzrt_rwlock_create(&shared_codetab_lock);
}
mzrt_rwlock_wrlock(shared_codetab_lock);
if (!shared_codetab_tree) if (!shared_codetab_tree)
shared_codetab_tree = malloc_node(0); shared_codetab_tree = malloc_node(0);
the_tree = shared_codetab_tree; the_tree = shared_codetab_tree;
@ -224,12 +218,6 @@ void scheme_jit_add_symbol(uintptr_t start, uintptr_t end, void *value, int gc_a
do_clear_symbols(the_tree, start, 0, 0, 0); do_clear_symbols(the_tree, start, 0, 0, 0);
} }
#endif #endif
#ifdef MZ_USE_PLACES
if (!gc_able) {
mzrt_rwlock_unlock(shared_codetab_lock);
}
#endif
} }
static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing) static int do_clear_symbols(void **t, uintptr_t start, int offset, uintptr_t addr, int clearing)