Date: Thu, 04 Dec 2014 19:37:10 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-threads@FreeBSD.org Subject: [Bug 195098] pthread lock performance degradation on single CPU VM Message-ID: <bug-195098-16-4wkTjnv3xa@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-195098-16@https.bugs.freebsd.org/bugzilla/> References: <bug-195098-16@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=195098 --- Comment #3 from Ed Maste <emaste@freebsd.org> --- It appears that in the "slow" case the repro code is spinning in the pthread_yield() at line 107 - i.e., trying to allow the contender threads run, but the main thread immediately resumes. 98 /* Wait until every thread is ready. */ 99 dbgprintf ("Main thread before synchronizing for round %d\n", repeat); 100 for (;;) 101 { 102 int ready_count = 0; 103 for (i = 0; i < THREAD_COUNT; i++) 104 ready_count += ready[i]; 105 if (ready_count == THREAD_COUNT) 106 break; 107 pthread_yield (); 108 } -- You are receiving this mail because: You are the assignee for the bug.help
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