From owner-freebsd-performance@FreeBSD.ORG Tue Apr 22 23:04:24 2014 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 23C0FBDE for ; Tue, 22 Apr 2014 23:04:24 +0000 (UTC) Received: from mail-qc0-x22f.google.com (mail-qc0-x22f.google.com [IPv6:2607:f8b0:400d:c01::22f]) (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 D33F11838 for ; Tue, 22 Apr 2014 23:04:23 +0000 (UTC) Received: by mail-qc0-f175.google.com with SMTP id e16so171372qcx.34 for ; Tue, 22 Apr 2014 16:04:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=xi8DS/coqaM3xkcYDJzbnw/CHswvIVC883Zjc3JZjs8=; b=O14cmk0CDZzQ8whJxXKQL3pYLBBP9trPIXGiRq+F73Ltra4dEg/Sgi1P0+sEUe7ce8 TxrDPZ6qRtFYuCofIw6obH4UHyJrLE0Hkk6ighKTnY8zT0gRWU/7Qsr8Y1H16KlWXomt PhF57GvYB8myhZZdSG5LdYEyWZGEGUuUrFDwRqlLDkpDMcKEDTYNCeEJbdqQ/JiNap3J 7yxEyTHyZSUOgwBaPZjknaQ6BYPx7FNO0AdeCNms9m21Ad4KSw1XhReus5BRL9jW/aXs XeGLfdjuHRZnbkwciam4nMdoI1vTt/symphewOhQ2YTod8NecaWSVRB1FvXYCh4dV/Ym u2Eg== MIME-Version: 1.0 X-Received: by 10.224.38.138 with SMTP id b10mr15617871qae.98.1398207863014; Tue, 22 Apr 2014 16:04:23 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.191.201 with HTTP; Tue, 22 Apr 2014 16:04:22 -0700 (PDT) In-Reply-To: References: <5327B9B7.3050103@gmail.com> <2610F490C952470C9D15999550F67068@multiplay.co.uk> <532A192A.1070509@gmail.com> Date: Tue, 22 Apr 2014 16:04:22 -0700 X-Google-Sender-Auth: 3wgQo0leiwD8tQE820ab9VRQrq4 Message-ID: Subject: Re: FreeBSD 10 and PostgreSQL 9.3 scalability issues From: Adrian Chadd To: Palle Girgensohn Content-Type: text/plain; charset=UTF-8 Cc: bsdmailinglist@googlegroups.com, FreeBSD Mailing Lists , Sean Chittenden , Petr Janda , Steven Hartland 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: Tue, 22 Apr 2014 23:04:24 -0000 Hi, Are you able to repeat these tests (for both 9.2 and 9.3) whilst grabbing some performance data from lock profiling and hwpmc? The benchmarking is great but it doesn't tell us enough information as to "why" things behave poorly compared to Linux and why the mmap drop isn't so great. What about with more clients? 64? 128? 256? Thanks! -a On 21 April 2014 14:11, Palle Girgensohn wrote: > > > 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 > _______________________________________________ > freebsd-performance@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org"