From owner-freebsd-hackers Sun Mar 8 21:16:10 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id VAA29681 for freebsd-hackers-outgoing; Sun, 8 Mar 1998 21:16:10 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from rover.village.org (rover.village.org [204.144.255.49]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id VAA29648 for ; Sun, 8 Mar 1998 21:16:01 -0800 (PST) (envelope-from imp@village.org) Received: from pencil-box.village.org [10.0.0.22] by rover.village.org with esmtp (Exim 1.71 #1) id 0yBuul-0005Np-00; Sun, 8 Mar 1998 22:15:51 -0700 Received: from pencil-box.village.org (localhost [127.0.0.1]) by pencil-box.village.org (8.8.8/8.8.3) with ESMTP id WAA04129; Sun, 8 Mar 1998 22:15:05 -0700 (MST) Message-Id: <199803090515.WAA04129@pencil-box.village.org> To: Mike Smith Subject: Re: kernel wishlist for web server performance Cc: Marc Slemko , hackers@FreeBSD.ORG In-reply-to: Your message of "Sat, 07 Mar 1998 21:54:12 PST." <199803080554.VAA08633@dingo.cdrom.com> References: <199803080554.VAA08633@dingo.cdrom.com> Date: Sun, 08 Mar 1998 22:15:05 -0700 From: "M. Warner Losh" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <199803080554.VAA08633@dingo.cdrom.com> Mike Smith writes: : I appreciate the conceptual niceness of what you're describing, but I : guess I'm not convinced that something like that would be worth the : cruft and effort involved. On most modern systems that I've played with, copy avoidance doesn't really help much at all. bcopy and friends run at about 50-75MB/s, while most networking and/or disk protocols are lucky to get into the 5-10M range (sustained). the copies that you are avoiding don't really hurt much and would be difficult to measure for most applications. I have had great difficulty speeding up a driver that I wrote for Solaris by eliminating some bcopy() calls. They tend not to be all that important for most applications.[*] Warner [*] if you are still running on 25MHz processors in embedded systems or on really slow hardware, this statement is completely bogus... To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message