From owner-freebsd-hackers Wed Apr 3 12:32:58 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from patrocles.silby.com (d107.as2.nwbl0.wi.voyager.net [169.207.92.107]) by hub.freebsd.org (Postfix) with ESMTP id 4F2D137B405 for ; Wed, 3 Apr 2002 12:32:39 -0800 (PST) Received: from patrocles.silby.com (localhost [127.0.0.1]) by patrocles.silby.com (8.12.2/8.12.2) with ESMTP id g342VeUH059432; Wed, 3 Apr 2002 20:31:40 -0600 (CST) (envelope-from silby@silby.com) Received: from localhost (silby@localhost) by patrocles.silby.com (8.12.2/8.12.2/Submit) with ESMTP id g342VbG8059429; Wed, 3 Apr 2002 20:31:38 -0600 (CST) X-Authentication-Warning: patrocles.silby.com: silby owned process doing -bs Date: Wed, 3 Apr 2002 20:31:37 -0600 (CST) From: Mike Silbersack To: John Regehr Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Linuxthreads on Linux vs FreeBSD performance question In-Reply-To: Message-ID: <20020403202732.K59420-100000@patrocles.silby.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, 3 Apr 2002, John Regehr wrote: > Anyway, I was speculating that the higher cost is either due to (1) a > failure, in FreeBSD, to avoid page table operations when switching > between threads in the same addres space, or (2) some other kind of > semantic mismatch between Linuxthreads and rfork. Is one of these > guesses right? > > Any help appreciated. Thanks, > > John Regehr You may be able to learn which is the case by building a kernel with profiling support and seeing where the hotspot is during your tests. Offhand, I'd guess that any of your ideas is possible. I don't believe that much time was spent optimizing the kernel for Linuxthreads. Have you tried benchmarking process to process context switch times to see if the results are similar? Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message