From owner-freebsd-fs Mon Aug 20 10: 8:14 2001 Delivered-To: freebsd-fs@freebsd.org Received: from femail12.sdc1.sfba.home.com (femail12.sdc1.sfba.home.com [24.0.95.108]) by hub.freebsd.org (Postfix) with ESMTP id BAC6237B41B for ; Mon, 20 Aug 2001 10:08:10 -0700 (PDT) (envelope-from jeff@expertcity.com) Received: from expertcity.com ([65.5.156.51]) by femail12.sdc1.sfba.home.com (InterMail vM.4.01.03.20 201-229-121-120-20010223) with ESMTP id <20010820170805.LDZX21782.femail12.sdc1.sfba.home.com@expertcity.com> for ; Mon, 20 Aug 2001 10:08:05 -0700 Message-ID: <3B8143F6.4030908@expertcity.com> Date: Mon, 20 Aug 2001 10:08:06 -0700 From: Jeff Behl User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; m18) Gecko/20010131 Netscape6/6.01 X-Accept-Language: en MIME-Version: 1.0 To: freebsd-fs@freebsd.org Subject: syncer delay? Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org howdy, We have a very time sensitive application that we think is being affected by the kernel syncer process. While doing a poll call, every 30 seconds we will have iterations that take 300+ ms longer than on average. This only started happening after our app started needing to log data to disk, and the delays are longer when there are more connections (more to write/log). I turned on IDE write caching (hw.ata.wc) but this has had no noticeable effect. What else can we do to try and minimize this hiccup every 30 seconds? Is adjusting the time between sync's a worthwhile approach (using sysctl)? We're using 4.3-RELEASE. thanks. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message