From owner-freebsd-stable@FreeBSD.ORG Thu Apr 15 13:23:30 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DC7FE1065670; Thu, 15 Apr 2010 13:23:29 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-qy0-f175.google.com (mail-qy0-f175.google.com [209.85.221.175]) by mx1.freebsd.org (Postfix) with ESMTP id 6290B8FC21; Thu, 15 Apr 2010 13:23:29 +0000 (UTC) Received: by qyk5 with SMTP id 5so1655865qyk.3 for ; Thu, 15 Apr 2010 06:23:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:received:message-id:subject:from:to:cc:content-type; bh=UrLXasOTZtGTm9LM9UkV7hw2T6N7jfggZMMdApIKYss=; b=eDlFFhiqXvSkrizTzsZBYy0itiwmtAbAO7h89F+t0V78Jdhs0a+X5UhryM9P+weS51 RsGE9zte6J3w7qJ0tOcybEHfzUMOc76XccbYJR+t7AyIV+dqX/sxUvWwyWruEwopwDs9 z36KGYvDjygbRbTx3BcmWHtR9PQ1K8F19FYaw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=pGBQcYtTQ8W4WNKIK8rzxloUyqvkQWacUzCtNqgKVjeJ+caibUcRug/p9IOTc0yvDN 6JAmT8bWeYkhjuAI+3B/j2zDZFWW0wU5i1hCY8YhNy0qOLmJK4gT41tkp5ws7JkFnjnq FYS6dThATHEwZqcFBdxASUGMqnYmVR+a5sixE= MIME-Version: 1.0 Received: by 10.229.85.147 with HTTP; Thu, 15 Apr 2010 06:23:28 -0700 (PDT) In-Reply-To: <4BC6D436.7060207@freebsd.org> References: <4BC402B7.5000400@modulus.org> <20100414.082109.29593248145846106.chat95@mac.com> <4BC5DEB4.1090208@freebsd.org> <4BC5F289.7020408@freebsd.org> <4BC6D436.7060207@freebsd.org> Date: Thu, 15 Apr 2010 08:23:28 -0500 Received: by 10.229.212.213 with SMTP id gt21mr2557961qcb.2.1271337808164; Thu, 15 Apr 2010 06:23:28 -0700 (PDT) Message-ID: From: Adam Vande More To: Andriy Gapon Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: alc@freebsd.org, Maho NAKATA , alan.l.cox@gmail.com, freebsd-stable@freebsd.org, als@modulus.org Subject: Re: How to reproduce: Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Apr 2010 13:23:30 -0000 On Thu, Apr 15, 2010 at 3:54 AM, Andriy Gapon wrote: > This is a good point. > But on the other hand, it means that our scheduler doesn't do a perfect job > here. BTW, I use ULE. > My observation is that when a number of CPU-intensive long running > processes is > less than or equal to number of cores, then the processes tend to stay on > the > same cores for a long time. > But if the number of the processes is greater, then they seem to jump from > core > to core a lot. > But I am not sure what would be an optimal strategy for that case. If we > try to > keep some lucky processes on the same core, then cpu time might be shared > unfairly. Shuffling cores provides more fairness, but can hurt total > performance. > Is is possible to add a tunable to the scheduler for it's aggressiveness in switching cores? -- Adam Vande More