From owner-freebsd-alpha Fri Jun 30 10:17:56 2000 Delivered-To: freebsd-alpha@freebsd.org Received: from wall.polstra.com (rtrwan160.accessone.com [206.213.115.74]) by hub.freebsd.org (Postfix) with ESMTP id E582137BA36 for ; Fri, 30 Jun 2000 10:17:53 -0700 (PDT) (envelope-from jdp@polstra.com) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.9.3/8.9.3) with ESMTP id KAA02935; Fri, 30 Jun 2000 10:17:52 -0700 (PDT) (envelope-from jdp@polstra.com) From: John Polstra Received: (from jdp@localhost) by vashon.polstra.com (8.9.3/8.9.1) id KAA25927; Fri, 30 Jun 2000 10:17:52 -0700 (PDT) (envelope-from jdp@polstra.com) Date: Fri, 30 Jun 2000 10:17:52 -0700 (PDT) Message-Id: <200006301717.KAA25927@vashon.polstra.com> To: tpnelson@echidna.stu.cowan.edu.au Subject: Re: Cache line size for the Alpha In-Reply-To: <395B0487.9D94D2A8@student.cowan.edu.au> References: <395A0EE8.28E6C524@student.cowan.edu.au> <200006291628.JAA23243@vashon.polstra.com> <395B0487.9D94D2A8@student.cowan.edu.au> Organization: Polstra & Co., Seattle, WA Cc: alpha@freebsd.org Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org In article <395B0487.9D94D2A8@student.cowan.edu.au>, Trent Nelson wrote: > > From the Alpha Architecture Handbook, v4.0, Appendix A.3: > > "Software locks are aligned quadwords and should be allocated > to large cache blocks that either contain no other data or > read-mostly data whose usage is correlated with the lock." > [Pg. 279-280] Thanks -- that settles the issue. > From what I've read, I think the biggest performance > consideration is the locality of the resource in contention. For > high contention locks, it seems desirable to ensure that the > spinlock code and the resource in contention are placed on separate > 128-byte cache block boundaries. The 128-byte figure confuses me. I thought the biggest cache line size you mentioned before was 64 bytes. Is a cache "block" different from a cache line? John -- John Polstra jdp@polstra.com 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-alpha" in the body of the message