From owner-freebsd-performance@FreeBSD.ORG Sat May 6 20:50:36 2006 Return-Path: X-Original-To: performance@FreeBSD.org Delivered-To: freebsd-performance@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A280B16A400; Sat, 6 May 2006 20:50:36 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 52EDA43D45; Sat, 6 May 2006 20:50:36 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id D88E946BD8; Sat, 6 May 2006 16:50:35 -0400 (EDT) Date: Sat, 6 May 2006 21:50:35 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Attila Nagy In-Reply-To: <445D07C1.7080403@fsn.hu> Message-ID: <20060506214838.Q46997@fledge.watson.org> References: <20060506150622.C17611@fledge.watson.org> <445D07C1.7080403@fsn.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: performance@FreeBSD.org, current@FreeBSD.org Subject: Re: Fine-grained locking for POSIX local sockets (UNIX domain sockets) X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 May 2006 20:50:36 -0000 On Sat, 6 May 2006, Attila Nagy wrote: > On 2006. 05. 06. 16:16, Robert Watson wrote: >> In local measurements, I have observed a 0% change in MySQL performance on >> uniprocessor systems, and on a dual-processor system I have observed a >> 4%-5% performance improvement with two client MySQL threads. > Just a quick, nowhere correct test: > http://people.fsn.hu/~bra/freebsd/20060506a-uds-fine-grain.diff/domsock.png > > The machine is a quad core Xeon LV server, the client side is sysbench, > accessing mysql 4.1.8 on a socket. Heap table, simple test. Which threading library is that with, btw? If libpthread, could you run the same test with libthr, and vice versa? I've noticed that libpthread has the interesting property that it greatly improves contention issues on certain locks when those locks are contended on within a process. The reason is that it avoids having threads within the process compete with themselves. The big locks threaded processes hit when contending with themselves are the file descriptor array lock and signal delivery related locks. Robert N M Watson