* generic/tclAlloc.c:

	* generic/tclInt.h:
	* generic/tclThreadAlloc.c (new):
	* unix/Makefile.in:
	* unix/tclUnixThrd.c:
	* win/Makefile.in:
	* win/tclWinInt.h:
	* win/tclWinThrd.c: added new threaded allocator contributed by
	AOL that significantly reduces lock contention when multiple
	threads are in use.  Only Windows and Unix implementations are
	ready, and the Windows one may need work.  It is only used by
	default on Unix for now, and requires that USE_THREAD_ALLOC be
	defined (--enable-threads on Unix will define this).


FossilOrigin-Name: 329bb4c2950b83d7f84e74e956bc925bbfd25684

1 files changed, 50 insertions, 0 deletions

diff --git a/unix/tclUnixThrd.c b/unix/tclUnixThrd.c
index 82b4d24..4084cbe 100644
--- a/unix/tclUnixThrd.c
+++ b/unix/tclUnixThrd.c
@@ -833,4 +833,54 @@ TclpInetNtoa(struct in_addr addr)
     return tsdPtr->nabuf;
 }
 
+/*
+ * Additions by AOL for specialized thread memory allocator.
+ */
+#ifdef USE_THREAD_ALLOC
+static int initialized = 0;
+static pthread_key_t	key;
+static pthread_once_t	once = PTHREAD_ONCE_INIT;
+
+Tcl_Mutex *
+TclpNewAllocMutex(void)
+{
+    struct lock {
+        Tcl_Mutex       tlock;
+        pthread_mutex_t plock;
+    } *lockPtr;
+
+    lockPtr = malloc(sizeof(struct lock));
+    if (lockPtr == NULL) {
+	panic("could not allocate lock");
+    }
+    lockPtr->tlock = (Tcl_Mutex) &lockPtr->plock;
+    pthread_mutex_init(&lockPtr->plock, NULL);
+    return &lockPtr->tlock;
+}
+
+static void
+InitKey(void)
+{
+    extern void TclFreeAllocCache(void *);
+
+    pthread_key_create(&key, TclFreeAllocCache);
+    initialized = 1;
+}
+
+void *
+TclpGetAllocCache(void)
+{
+    if (!initialized) {
+	pthread_once(&once, InitKey);
+    }
+    return pthread_getspecific(key);
+}
+
+void
+TclpSetAllocCache(void *arg)
+{
+    pthread_setspecific(key, arg);
+}
+
+#endif /* USE_THREAD_ALLOC */
 #endif /* TCL_THREADS */