[or-cvs] [tor/maint-0.2.1 2/2] testsuite: Prevent the main thread from starving the worker threads

[nickm at torproject.org]

Author: Peter Palfrader <peter at palfrader.org>
Date: Tue, 13 Apr 2010 00:10:56 +0200
Subject: testsuite: Prevent the main thread from starving the worker threads
Commit: 5e679acc72a2648c38a3ee3a2b05cd5b75906568

---
 changes/weasel-testuite-thread-fixes |    5 +++++
 src/or/test.c                        |    9 +++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/changes/weasel-testuite-thread-fixes b/changes/weasel-testuite-thread-fixes
index 8fed729..4c32c38 100644
--- a/changes/weasel-testuite-thread-fixes
+++ b/changes/weasel-testuite-thread-fixes
@@ -1,3 +1,8 @@
   o Minor bugfixes:
     - Testsuite:  In the util/threads test no longer free the test_mutex
       before all worker threads have finished.
+    - Testsuite:  The master thread could starve the worker threads quite
+      badly on certain systems, causing them to run only partially in
+      the allowed window.  This resulted in test failures.  Now the master
+      thread sleeps occasionally for a few microseconds while the two
+      worker-threads compete for the mutex.
diff --git a/src/or/test.c b/src/or/test.c
index 652a4ee..14ba953 100644
--- a/src/or/test.c
+++ b/src/or/test.c
@@ -2326,6 +2326,11 @@ test_util_threads(void)
   char *s1 = NULL, *s2 = NULL;
   int done = 0, timedout = 0;
   time_t started;
+#ifndef MS_WINDOWS
+  struct timeval tv;
+  tv.tv_sec=0;
+  tv.tv_usec=10;
+#endif
 #ifndef TOR_IS_MULTITHREADED
   /* Skip this test if we aren't threading. We should be threading most
    * everywhere by now. */
@@ -2355,6 +2360,10 @@ test_util_threads(void)
       timedout = done = 1;
     }
     tor_mutex_release(_thread_test_mutex);
+#ifndef MS_WINDOWS
+    /* Prevent the main thread from starving the worker threads. */
+    select(0, NULL, NULL, NULL, &tv);
+#endif
   }
 
   tor_mutex_acquire(_thread_test_start1);
-- 
1.6.5