From owner-freebsd-hackers@FreeBSD.ORG Sun Jul 13 10:09:52 2008 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B98BC1065675 for ; Sun, 13 Jul 2008 10:09:52 +0000 (UTC) (envelope-from kris@FreeBSD.org) Received: from weak.local (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 865838FC1E; Sun, 13 Jul 2008 10:09:51 +0000 (UTC) (envelope-from kris@FreeBSD.org) Message-ID: <4879D46E.7080104@FreeBSD.org> Date: Sun, 13 Jul 2008 12:09:50 +0200 From: Kris Kennaway User-Agent: Thunderbird 2.0.0.14 (Macintosh/20080421) MIME-Version: 1.0 To: Nate Eldredge References: <4879563B.5090201@FreeBSD.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@FreeBSD.org Subject: Re: SCHED_4BSD bad interactivity on 7.0 vs 6.3 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 13 Jul 2008 10:09:52 -0000 Nate Eldredge wrote: > On Sun, 13 Jul 2008, Kris Kennaway wrote: > >> Nate Eldredge wrote: >>> Hi folks, >>> >>> Hopefully this is a good list for this topic. >>> >>> It seems like there has been a regression in interactivity from >>> 6.3-RELEASE to 7.0-RELEASE when using the SCHED_4BSD scheduler. >>> After upgrading my single-cpu amd64 box, 7.0 has much worse latency. >>> When running a kernel compile, there is a noticeable lag to echo my >>> typing or scroll my browser windows, and playing an mp3 frequently >>> cuts out for a second or two. This did not happen on 6.3-RELEASE. >> >> Are you sure it's not the x.org server bug that was present in the >> version shipped with 7.0? Update to the latest version and see if >> your X interactivity improves. > > Yes, I had not yet upgraded my x.org port when testing this, so it was > the same x.org that was fine under 6.3. Also: > >>> I wrote a small program which forks two processes that run >>> gettimeofday() in a tight loop to see how long they get scheduled >>> out. On 6.3 the maximum latency is usually under 100 ms. On 7.0 it >>> is 500 ms or more even when nothing else is running on the system. >>> When a compile is also running it is sometimes 1400 ms or more. > > This test shows a difference even in single user mode, when X is not > running at all. > It shows *a* difference, but perhaps not the *same* difference. Please humour me and rule it out. Kris