From owner-freebsd-current@FreeBSD.ORG Wed Apr 2 12:56:08 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A7B6B37B401 for ; Wed, 2 Apr 2003 12:56:08 -0800 (PST) Received: from canning.wemm.org (canning.wemm.org [192.203.228.65]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4C9DB43F93 for ; Wed, 2 Apr 2003 12:56:08 -0800 (PST) (envelope-from peter@wemm.org) Received: from wemm.org (localhost [127.0.0.1]) by canning.wemm.org (Postfix) with ESMTP id 2FCF82A8A5; Wed, 2 Apr 2003 12:56:08 -0800 (PST) (envelope-from peter@wemm.org) X-Mailer: exmh version 2.5 07/13/2001 with nmh-1.0.4 To: Terry Lambert In-Reply-To: <3E8A9101.66FE4135@mindspring.com> Date: Wed, 02 Apr 2003 12:56:08 -0800 From: Peter Wemm Message-Id: <20030402205608.2FCF82A8A5@canning.wemm.org> cc: csujun@21cn.com cc: current@FreeBSD.org Subject: Re: libthr and 1:1 threading. X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Apr 2003 20:56:09 -0000 Terry Lambert wrote: > Jun Su wrote: > > > [ ... 1:1 kernel threads implementation ... ] > > > > A benchmark would be interested. > > This request doesn't make sense. > > The primary performance reasoning behind a 1:1 kernel threading > implementation, relative to the user space single kernel entry > scheduler in the libc_r implementation is SMP scalability for > threaded applications. No. It gives the ability for a thread to block on a syscall without stalling the entire system. Just try using mysqld on a system using libc_r and heavy disk IO. You can't select() on a read() from disk. Thats the ultimate reason to do it. The SMP parallelism is a bonus. Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5