Date: Tue, 08 Jun 2004 09:17:41 +0800 From: David Xu <davidxu@freebsd.org> To: Peter Wemm <peter@wemm.org> Cc: freebsd-threads@freebsd.org Subject: Re: [tjr@FreeBSD.org: cvscommit:src/lib/libpthread/arch/amd64/amd 64 context.S] Message-ID: <40C513B5.8070406@freebsd.org> In-Reply-To: <200406071810.23069.peter@wemm.org> References: <200406071810.23069.peter@wemm.org>
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Peter Wemm wrote: > On Monday 07 June 2004 06:10 pm, David Xu wrote: > >>Is there any reason to use memory indirect jump ? did you >>have benchmarked context switch speed before and after this commit ? >>I won't use such indirect jump in speed sensitive case, it is >>not CPU branch trace cache friendly, it is better to use >>ret to match call in up level. > > > Because the return address is already on the higher level stack frame, > and copying it (read/write/ret) is more awkward than the read+indirect > jump. Unfortunately, we can't indirectly access the flags register. > I would like someone to test it: http://people.freebsd.org/~davidxu/kse/test/ctxswitch.c tell me the result before and after this commit. > >>David Xu >> >>Tim Robbins wrote: >> >>>Anyone who has resorted to using libc_r instead of libpthread on >>>amd64 should update their sources (ensuring they get context.S >>>revision 1.6), rebuild and reinstall libpthread (or world), then >>>give it another try. The bug I just fixed looks to have been >>>responsible for the mysterious crashes I was seeing in >>>Mozilla/Firefox, XMMS and GNOME. >>> >>> >>>Tim >>> >>>----- Forwarded message from "Tim J. Robbins" <tjr@FreeBSD.org> >>>----- >>> >>>From: "Tim J. Robbins" <tjr@FreeBSD.org> >>>Date: Mon, 7 Jun 2004 21:25:17 +0000 (UTC) >>>To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, >>> cvs-all@FreeBSD.org >>>Subject: cvs commit: src/lib/libpthread/arch/amd64/amd64 context.S >>>X-FreeBSD-CVS-Branch: HEAD >>>Precedence: bulk >>>X-Loop: FreeBSD.ORG >>>X-Bogosity: No, tests=bogofilter, spamicity=0.000000, >>>version=0.15.7 >>> >>>tjr 2004-06-07 21:25:16 UTC >>> >>> FreeBSD src repository >>> >>> Modified files: >>> lib/libpthread/arch/amd64/amd64 context.S >>> Log: >>> Avoid clobbering the red zone when running on the new context's >>>stack in _amd64_restore_context(). >>> >>> Revision Changes Path >>> 1.6 +5 -0 >>>src/lib/libpthread/arch/amd64/amd64/context.S >>> >>>----- End forwarded message ----- >>>_______________________________________________ >>>freebsd-threads@freebsd.org mailing list >>>http://lists.freebsd.org/mailman/listinfo/freebsd-threads >>>To unsubscribe, send any mail to >>>"freebsd-threads-unsubscribe@freebsd.org" >> >>_______________________________________________ >>freebsd-amd64@freebsd.org mailing list >>http://lists.freebsd.org/mailman/listinfo/freebsd-amd64 >>To unsubscribe, send any mail to >>"freebsd-amd64-unsubscribe@freebsd.org" > >
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