From owner-freebsd-hackers@FreeBSD.ORG Sun Jul 13 19:38:24 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 D30F2106566B; Sun, 13 Jul 2008 19:38:24 +0000 (UTC) (envelope-from neldredge@math.ucsd.edu) Received: from euclid.ucsd.edu (euclid.ucsd.edu [132.239.145.52]) by mx1.freebsd.org (Postfix) with ESMTP id A905F8FC12; Sun, 13 Jul 2008 19:38:24 +0000 (UTC) (envelope-from neldredge@math.ucsd.edu) Received: from zeno.ucsd.edu (zeno.ucsd.edu [132.239.145.22]) by euclid.ucsd.edu (8.11.7p3+Sun/8.11.7) with ESMTP id m6DJcOB04961; Sun, 13 Jul 2008 12:38:24 -0700 (PDT) Received: from localhost (neldredg@localhost) by zeno.ucsd.edu (8.11.7p3+Sun/8.11.7) with ESMTP id m6DJcON11422; Sun, 13 Jul 2008 12:38:24 -0700 (PDT) X-Authentication-Warning: zeno.ucsd.edu: neldredg owned process doing -bs Date: Sun, 13 Jul 2008 12:38:24 -0700 (PDT) From: Nate Eldredge X-X-Sender: neldredg@zeno.ucsd.edu To: Kris Kennaway In-Reply-To: <4879D46E.7080104@FreeBSD.org> Message-ID: References: <4879563B.5090201@FreeBSD.org> <4879D46E.7080104@FreeBSD.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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 19:38:24 -0000 On Sun, 13 Jul 2008, Kris Kennaway wrote: > 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. Okay. I am in the process of recompiling all my ports, so after that is done I will boot with a GENERIC kernel and see what happens. -- Nate Eldredge neldredge@math.ucsd.edu