Date: Wed, 19 Dec 2007 21:53:56 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Warner Losh <imp@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/lib/libc/stdtime localtime.c Message-ID: <20071219210516.I37050@delplex.bde.org> In-Reply-To: <200712190430.lBJ4UB7M018392@repoman.freebsd.org> References: <200712190430.lBJ4UB7M018392@repoman.freebsd.org>
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On Wed, 19 Dec 2007, Warner Losh wrote: > imp 2007-12-19 04:30:11 UTC > > FreeBSD src repository > > Modified files: > lib/libc/stdtime localtime.c > Log: > Reduce lock contention for simple cases. > > # this really should be done with pthread_once, but I've debugged this code. > > Reviewed by: arch@ Reviewers weren't happy with this. I now think that the only bug in it is that it unnecesarily depends i386 memory semantics (that writes are not reordered). There should be a write barrier before the flag is set, to ensure that the writes which initialize things occur before the write that sets the flag. Bruce
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