From: Brian Pane <brianp@apache.org>
Date: Fri, 19 Apr 2002 08:02:00 +0000 (+0000)
Subject: Some code transformations to improve the generated assembly
X-Git-Tag: 2.0.36~150
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c3a94b86c1ca97178e029fff42b0ab90f508a79;p=thirdparty%2Fapache%2Fhttpd.git

Some code transformations to improve the generated assembly
code within the critical region inside the spin locks.  (Shortening
this code path reduces the probability that we'll have to spin.)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94706 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/server/mpm/experimental/leader/leader.c b/server/mpm/experimental/leader/leader.c
index a3fe24e50f8..3581b473d1b 100644
--- a/server/mpm/experimental/leader/leader.c
+++ b/server/mpm/experimental/leader/leader.c
@@ -247,11 +247,11 @@ static apr_proc_mutex_t *accept_mutex;
 /* Structure used to wake up an idle worker thread
  */
 struct worker_wakeup_info {
-    apr_thread_cond_t *cond;
-    apr_thread_mutex_t *mutex;
     apr_uint32_t next; /* index into worker_wakeups array,
                         * used to build a linked list
                         */
+    apr_thread_cond_t *cond;
+    apr_thread_mutex_t *mutex;
 };
 
 static worker_wakeup_info *worker_wakeup_create(apr_pool_t *pool)
@@ -349,9 +349,8 @@ static apr_status_t worker_stack_awaken_next(worker_stack *stack)
         }
         else {
             worker_wakeup_info *wakeup = worker_wakeups[first];
-            apr_uint32_t new_state = state & ~STACK_FIRST;
-            new_state |= wakeup->next;
-            if (apr_atomic_cas(&(stack->state), new_state, state) != state) {
+            if (apr_atomic_cas(&(stack->state), (state ^ first) | wakeup->next,
+                               state) != state) {
                 continue;
             }
             else {