Date: Sun, 18 Mar 2012 19:50:15 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: David Xu <davidxu@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r232209 - in head: lib/libthr/thread sys/kern Message-ID: <20120318185014.GK1340@garage.freebsd.pl> In-Reply-To: <201202271338.q1RDcqEQ020033@svn.freebsd.org> References: <201202271338.q1RDcqEQ020033@svn.freebsd.org>
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--Ms5iOKSBOB9YS8zC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 27, 2012 at 01:38:52PM +0000, David Xu wrote: > Author: davidxu > Date: Mon Feb 27 13:38:52 2012 > New Revision: 232209 > URL: http://svn.freebsd.org/changeset/base/232209 >=20 > Log: > Follow changes made in revision 232144, pass absolute timeout to kernel, > this eliminates a clock_gettime() syscall. This or some other change has broken CLOCK_MONOTONIC usage with condition variables. You should be able to reproduce this by something like this: pthread_cond_t cv; pthread_condattr_t attr; pthread_mutex_t lock; struct timespec ts; int error; (void)pthread_mutex_init(&lock, NULL); (void)pthread_condattr_init(&attr); (void)pthread_condattr_setclock(&attr, CLOCK_MONOTONIC); (void)pthread_cond_init(&cv, &attr); (void)pthread_condattr_destroy(&attr); (void)clock_gettime(CLOCK_MONOTONIC, &ts); ts.tv_sec +=3D 10; (void)pthread_mutex_lock(&lock); (void)pthread_cond_timedwait(&cv, &lock, &ts); (void)pthread_mutex_unlock(&lock); This should timeout after 10 seconds, but pthread_cond_timedwait(3) returns immediately with ETIMEDOUT. CLOCK_REALTIME works properly. Bascially pthread_condattr_setclock(&attr, CLOCK_MONOTONIC) is no-op. If you change CLOCK_MONOTONIC to CLOCK_REALTIME in clock_gettime(2) call, it will timeout after 10 seconds. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl --Ms5iOKSBOB9YS8zC Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAk9mLmYACgkQForvXbEpPzS+lQCgoKdnHns+Q/E+jvCf9O9RS42y 2bQAoIAg8CMWpS3fxaqha7beqw9bG7JN =UPcG -----END PGP SIGNATURE----- --Ms5iOKSBOB9YS8zC--
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