Date: Thu, 23 Feb 2012 08:07:49 +0800 From: David Xu <listlog2011@gmail.com> To: Jilles Tjoelker <jilles@stack.nl> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, David Xu <davidxu@FreeBSD.org> Subject: Re: svn commit: r231989 - in head: lib/libthr/thread sys/kern sys/sys Message-ID: <4F458355.8090405@gmail.com> In-Reply-To: <20120222234254.GC95122@stack.nl> References: <201202220322.q1M3MoFE032330@svn.freebsd.org> <20120222234254.GC95122@stack.nl>
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On 2012/2/23 7:42, Jilles Tjoelker wrote: > On Wed, Feb 22, 2012 at 03:22:50AM +0000, David Xu wrote: >> Author: davidxu >> Date: Wed Feb 22 03:22:49 2012 >> New Revision: 231989 >> URL: http://svn.freebsd.org/changeset/base/231989 >> Log: >> Use unused fourth argument of umtx_op to pass flags to kernel for operation >> UMTX_OP_WAIT. Upper 16bits is enough to hold a clock id, and lower >> 16bits is used to pass flags. The change saves a clock_gettime() syscall >> from libthr. >> Modified: >> head/lib/libthr/thread/thr_umtx.c >> head/sys/kern/kern_umtx.c >> head/sys/sys/umtx.h >> >> Modified: head/lib/libthr/thread/thr_umtx.c >> ============================================================================== >> --- head/lib/libthr/thread/thr_umtx.c Wed Feb 22 01:50:13 2012 (r231988) >> +++ head/lib/libthr/thread/thr_umtx.c Wed Feb 22 03:22:49 2012 (r231989) >> @@ -200,20 +200,10 @@ int >> + abstime != NULL ? (void *)(uintptr_t)((clockid<< 16) | UMTX_WAIT_ABSTIME) : 0, > Please check that this shift does not lose any information (i.e., > clockid>= 0&& clockid<= 0xFFFF) before doing it. > > Implementing clock_getcpuclockid() will require clockids greater than > 65535 because such clockids contain a process id. > In which document said the clock id includes a process id ? I think the clock_getcpuclockid() is a simplified version of getrusage().
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