From owner-freebsd-performance@FreeBSD.ORG Mon Apr 21 22:52:38 2014 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3A7959B0 for ; Mon, 21 Apr 2014 22:52:38 +0000 (UTC) Received: from mail-yh0-f63.google.com (mail-yh0-f63.google.com [209.85.213.63]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id EBF9912D3 for ; Mon, 21 Apr 2014 22:52:36 +0000 (UTC) Received: by mail-yh0-f63.google.com with SMTP id 29so1273816yhl.8 for ; Mon, 21 Apr 2014 15:52:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type; bh=lEZoLCK7FiDgEb0CO1IOfOytG3gg2BFULA+IUJZoGpc=; b=VD/17Ycails/vkZitqCxRY7jH7rwq83ahJEJYeSCHOLW5ZzvNQPhA3BE3jxXXk4i2f rPOMwNKMUTOCSGcAVmfSRzRyz2ibGR8ODkp6fljwnuLd3Ee9vI3zcu22rcQTX0KhUWCZ ByIZqiuGuP9Q1xP6RFhnXhnKlEpxayAu79cGtcW5Abtz8gJ/Me9CUE0bXIN7qIp4iAfX OmBWsJjKL+h+SXBmVwSTNtGGKDo8/ZKFvb3/kHbtH3qpptLDv5kQMaQ/+HpfUrB/5q9r EPo1C96qrtRyWMqqZrVE7W6svfxUdqhGHYH1LVe9HPfNFysCqEeu4WEG2EKZtN7eAVAS kqRw== X-Gm-Message-State: ALoCoQnIkm6Oj8IQFYqo6LoPUnT3s+jqrNmo/r4S5lFWYhc+jmXmxFirc8R7HLBNIICjOCV9Kick X-Received: by 10.140.36.6 with SMTP id o6mr54108qgo.26.1398114702242; Mon, 21 Apr 2014 14:11:42 -0700 (PDT) X-Google-Doc-Id: e87f9ad4ab539159 X-Google-Web-Client: true Date: Mon, 21 Apr 2014 14:11:41 -0700 (PDT) From: Palle Girgensohn To: bsdmailinglist@googlegroups.com Message-Id: In-Reply-To: References: <5327B9B7.3050103@gmail.com> <2610F490C952470C9D15999550F67068@multiplay.co.uk> <532A192A.1070509@gmail.com> Subject: Re: FreeBSD 10 and PostgreSQL 9.3 scalability issues MIME-Version: 1.0 X-Google-IP: 79.136.43.145 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: sean@chittenden.org, Steven Hartland , freebsd-performance@freebsd.org, Petr Janda , adrian@FreeBSD.org X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Apr 2014 22:52:38 -0000 Den torsdagen den 20:e mars 2014 kl. 00:33:10 UTC+1 skrev Sean Chittenden: > > > As far as I know, the test was done on both UFS2 and ZFS and the > > difference was marginal. > > As Adrian pointed out, there is an mmap(2) mutex in the way. Starting in > PostgreSQL 9.3, shared buffers are allocated out of mmap(2) instead of shm. > shm is only used to notify the PostgreSQL postmaster that a child process > exited/crashed (when a pid detaches from a shm segment, there is a kernel > event, but there is no kernel event when detaching from an mmap(2) region). > -sc > > http://www.postgresql.org/docs/9.3/static/release-9-3.html#AEN115039 > > > >>> Just want to share these pgbench results done by DragonFlyBSD, and > would > >>> like some input on why these numbers look so bad and what can be done > to > >>> improve (ie. kernel tunables etc) the performance. > >>> > >>> > http://lists.dragonflybsd.org/pipermail/users/attachments/20140310/4250b961/attachment-0001.pdf > >>> > >> > >> > >> Do you have the ability to test with FreeBSD 8.x and 9.x to see if this > is > >> regression? > >> > >> Also you don't mention the FS used in each case, so I'm wondering if > you > >> used a ZFS install of FreeBSD which could help to explain things. > > > -- > Sean Chittenden > se...@chittenden.org > > > Hi, There is a fresh thread about this in postgresql-hackers [1]. There are two parallel approaches suggested there, where one is to have an option to continue using the old SYSV shared memory in PostgreSQL, and the other is the suggestion that "somebody needs to hold the FreeBSD folks' feet to the fire about when we can expect to see a fix from their side." Looking at the original post in this thread, it seems to me that FreeBSD has scalability problems beyond what the SYSV vs mmap change in PostgreSQL introduces? Check my test of PostgreSQL 9.2 vs 9.3 on FreeBSD 10.0 at [1]. The difference between PG92 and PG93 is not huge, ~17%. The difference between FreeBSD and the other OS:es in this thread's original post's performance chart seems to be about a lot more? Palle [1] http://www.postgresql.org/message-id/2AE143D2-87D3-4AD1-AC78-CE2258230C05@FreeBSD.org