From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 5 20:52:16 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id CBCBA63D for ; Mon, 5 Nov 2012 20:52:16 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id 4B9708FC12 for ; Mon, 5 Nov 2012 20:52:15 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id b5so5670174lbd.13 for ; Mon, 05 Nov 2012 12:52:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=sboeQbIuShItXj0hwce2SnZfwjPNxgr5ighX9r3/5AA=; b=HivQ/LGgSXF1JRbpVk5dvQAcBrn+nzTxxUv4FS/eZDYbSmOAVz/v1kBszhQOhAgYUg f5hB1sjFhlvxsiis1jrTQRiYheqfvHz5HowB0rMREp9KYrtHWABK1/D0ugJwqU0gompb Ant+3So6J/PRvSr/qn3qzG89B5pTOYmDJ4lNxa9hOw7nGWaPXLDDYxoba8rfJjnkLa7i nJrllSKua9UylNfF0FZ8zY2avK9g1CWBvFrJgAo+/lN/MhbBRqZYnm5/4pgSC3bh5tCy lLLaoeKFRwwkPMizRNBYnQqlcFfE5Huq8HEgHKlVjECJh8E3KRqbsZZzLtj2DgTwf0yZ +zJg== MIME-Version: 1.0 Received: by 10.152.106.212 with SMTP id gw20mr10326286lab.8.1352148734702; Mon, 05 Nov 2012 12:52:14 -0800 (PST) Received: by 10.112.144.101 with HTTP; Mon, 5 Nov 2012 12:52:14 -0800 (PST) In-Reply-To: <50980ADD.4010402@rawbw.com> References: <50980ADD.4010402@rawbw.com> Date: Mon, 5 Nov 2012 12:52:14 -0800 Message-ID: Subject: Re: pgbench performance is lagging compared to Linux and DragonflyBSD? From: Garrett Cooper To: Yuri Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Nov 2012 20:52:16 -0000 On Mon, Nov 5, 2012 at 10:52 AM, Yuri wrote: > There is the post by DragonflyBSD folks that claims that Linux and > DragonflyBSD are quite ahead of FreeBSD on pgbench test on 12 Core 2x Xeon > X5650 with 24 threads. > Here are their results with graphs: http://lists.dragonflybsd.org/** > pipermail/users/attachments/**20121010/7996ff88/attachment-**0002.pdf > And here is their original post: http://lists.dragonflybsd.org/** > pipermail/users/2012-October/**017536.html > > I am not sure if this is the problem of some sysctl or kernel parameters > or some serious system issue. > > It looks like the DragonflyBSD folks made a goal to do well on pgbench and > got to the level of ~88% of linux with 80 clients. The important item that has been left out (or is just implied as OS level defaults) is sysctl/tunable variables set in the *BSD OSes (on DFly, FreeBSD, and NetBSD). Unfortunately (based on my experience) FreeBSD could be a lot better when it comes to defaults, and more tuning is required to get better performance. So if they're working with the OS defaults, this might not be a fair equivalent to the best performance that FreeBSD can yield, but it's probably fair to do this for the sake of repeatability and to prove what these OSes can do out of the box. This is in addition to the [lock] contention issues that jeffr@ and a few others are working on alleviating. FWIW, I think that the last time scheduler benchmarks from anyone at @FreeBSD.org (was kris@ the last one, or has flo@ run benchmarks since then? My Googling is a bit inconclusive) was run was several years ago as well, so if Linux has improved I'm not at all surprised. However, please also take into consideration that the hardware then and the hardware now are grossly different. So the interactions between the hardware then and the hardware now might differ greatly. In short, more inspection needs to be done to figure out whether or not the findings are true [with caveats] or false. Thanks, -Garrett