From owner-freebsd-hackers@FreeBSD.ORG Tue Mar 1 19:20:54 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8260A16A4CE for ; Tue, 1 Mar 2005 19:20:54 +0000 (GMT) Received: from rproxy.gmail.com (rproxy.gmail.com [64.233.170.206]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1028C43D1F for ; Tue, 1 Mar 2005 19:20:53 +0000 (GMT) (envelope-from sarath.kamisetty@gmail.com) Received: by rproxy.gmail.com with SMTP id j1so1319687rnf for ; Tue, 01 Mar 2005 11:20:52 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:references; b=X+lQQFSl4Wj4oUkTCOrPc9z1Ls4VFlIysbRsXDqeB6R6BBcN6XktansaoqyeKX+eR54/SXA3gfvWYTY9Tgid7b5+gbjrhVBfVnWTkYMq6dNI1hbacxt5Xu054+QfJfhkjCUT6BIhLMNVr4X7e8Sz/GYJLqfm6iUKC6/2E+bgNSI= Received: by 10.38.75.43 with SMTP id x43mr134755rna; Tue, 01 Mar 2005 11:20:25 -0800 (PST) Received: by 10.39.3.1 with HTTP; Tue, 1 Mar 2005 11:20:23 -0800 (PST) Message-ID: <641e6aa9050301112016d316bb@mail.gmail.com> Date: Tue, 1 Mar 2005 11:20:23 -0800 From: Sarath Kamisetty To: Julian Elischer In-Reply-To: <4222D5A2.9010301@elischer.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit References: <001a01c51d6d$d50ce500$abe243a4@ash> <4222D5A2.9010301@elischer.org> cc: freebsd-hackers@freebsd.org cc: Ashwin Chandra Subject: Re: sched_4BSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Sarath Kamisetty List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Mar 2005 19:20:54 -0000 Hi, How does Linux handle this ? Any idea ? Thanks, Sarat On Mon, 28 Feb 2005 00:26:10 -0800, Julian Elischer wrote: > Ashwin Chandra wrote: > > I wanted to get some clarification about the 4BSD scheduler. I am sort of > > confused why there are two forms of scheduling, one done between processes and > > another done between threads in a process. The priority calculations seem to be > > done only with processes and I assume that the global run queue holds processes, > > not threads. Also why is there only 1 run queue for 1 CPU. What happens to > > blocked processes and ready to be runned processes? > > Part of the challenge of adding threads to a system is to make it hard for a > threaded process to "flood" the system run queues so that other processes > get no cpu time. > > The scheme in the current freeBSD schedulers is a "crude" method, by which > only a limitted number of threads per process are allowed to be added to > the system run queue. RUnnable hreads fo r aprocess are kept on a run queue for > the process and only the highest N prioriy hreads are actually put on the > system run queue. > > This is by no means the best way, but rather the > easiest way. I am hoping that some PhD candidate somewhere will decide > that thread scheduling is his topic and will figure out a better way > of doing this. > > both run queues hold threads. This is still a place wjere a lot > of work can be done. > > :-) > > > > > > Ash > > _______________________________________________ > > freebsd-hackers@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >