Date: Sun, 31 Mar 2002 09:52:36 -0800 (PST) From: John Polstra <jdp@polstra.com> To: smp@freebsd.org Cc: dillon@apollo.backplane.com Subject: Re: RE: Syscall contention tests return, userret() bugs/issues. Message-ID: <200203311752.g2VHqab18408@vashon.polstra.com> In-Reply-To: <200203311747.g2VHlII89488@apollo.backplane.com> References: <XFMail.20020329155622.jhb@FreeBSD.org> <200203292207.g2TM7Fi67491@apollo.backplane.com> <200203311729.g2VHT5h18352@vashon.polstra.com> <200203311747.g2VHlII89488@apollo.backplane.com>
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In article <200203311747.g2VHlII89488@apollo.backplane.com>, Matthew Dillon <dillon@apollo.backplane.com> wrote: > > :> the cache, on IA32, it's write-through to main-memory which > :> invalidates all other cpu's caches for that cache line. > : > :No, it's not nearly that bad. See section 9.2 of the IA-32 Intel > :Architecture Software Developer's Manual, Volume 3 (24547203.pdf from > :developer.intel.com). It describes what happens in a couple of > :different scenarios, for example: > > This is not a case that typically occurs. Because intel caches are > write-through the processor that does the write will flush the dirty > cache line to main memory in fairly short order. Why do you keep saying the Intel caches are write-through? They've been write-back since the Pentium. See table 9-2 in the same document I cited before. John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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