From owner-freebsd-hackers Sun Feb 24 10:15:30 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 8D3A037B404 for ; Sun, 24 Feb 2002 10:15:26 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id g1OIFOV83527; Sun, 24 Feb 2002 10:15:24 -0800 (PST) (envelope-from dillon) Date: Sun, 24 Feb 2002 10:15:24 -0800 (PST) From: Matthew Dillon Message-Id: <200202241815.g1OIFOV83527@apollo.backplane.com> To: Andrew Mobbs Cc: hackers@FreeBSD.ORG Subject: Re: Test patch for msync/object-flushing performance (for stable) References: <15478.31998.459219.178549@chiark.greenend.org.uk> <200202222042.g1MKg4u22700@apollo.backplane.com> <200202222201.g1MM1f431236@apollo.backplane.com> <15481.61.57511.222531@chiark.greenend.org.uk> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Andrew, thanks for running these tests! They confirm exactly what I expected. I would like to improve bit 1 a bit more, but I think it is good enough to stage into the system with the default set to 3. In particular, I found that when you have a huge mmap()'d area and you msync() a small portion of it, bit 0 (case 1) results in phenominally better cpu performance above and beyond the lower fragmentation because msync() doesn't have to scan the entire object's memq. This should have a large positive effect on a number of applications. -Matt Matthew Dillon : vm.msync_flush_flags : | 0 | 1 | 2 | 3 | :-------+-------+-------+-------+-------| :write | 519 | 517 | 1632 | 519 | :sync | 2227 | 176 | 848 | 177 | :-------+-------+-------+-------+-------| :write | 514 | 517 | 518 | 516 | :sync | 2215 | 175 | 2219 | 176 | :-------+-------+-------+-------+-------| :write | 511 | 649 | 517 | 513 | :sync | 2209 | 125 | 2223 | 176 | :-------+-------+-------+-------+-------| :write | 514 | 518 | 515 | 517 | :sync | 2217 | 176 | 2209 | 176 | :-------+-------+-------+-------+-------| :write | 516 | 516 | 517 | 518 | :sync | 2219 | 176 | 2222 | 177 | : :Nearly 13 times improvement in sync times, very nice. :-- :Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message