From owner-cvs-all Tue Jun 26 4:29:54 2001 Delivered-To: cvs-all@freebsd.org Received: from green.bikeshed.org (freefall.freebsd.org [216.136.204.21]) by hub.freebsd.org (Postfix) with ESMTP id BAFB637B406; Tue, 26 Jun 2001 04:29:34 -0700 (PDT) (envelope-from green@green.bikeshed.org) Received: from localhost (green@localhost) by green.bikeshed.org (8.11.2/8.11.1) with ESMTP id f5OLfc176777; Sun, 24 Jun 2001 17:41:39 -0400 (EDT) (envelope-from green@green.bikeshed.org) Message-Id: <200106242141.f5OLfc176777@green.bikeshed.org> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: "Jonathan Lemon Alfred Perlstein" Cc: Mike Silbersack , Matt Dillon , Mike Silbersack , cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, jlemon@FreeBSD.org, bmilekic@FreeBSD.org Subject: Re: cvs commit: src/sys/netinet tcp_input.c tcp_output.c tcp_subr.c tcp_timer.c tcp_usrreq.c tcp_var.h In-Reply-To: Message from "Jonathan Lemon Alfred Perlstein" of "Sun, 24 Jun 2001 13:58:28 CDT." <20010624135828.A64836@sneakerz.org> From: "Brian F. Feldman" Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 24 Jun 2001 17:41:38 -0400 Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG "Jonathan Lemon Alfred Perlstein" wrote: > * Mike Silbersack [010623 13:14] wrote: > > > > On Sat, 23 Jun 2001, Matt Dillon wrote: > > > > > Yes, there's no question bzero() should be removed. The subroutine > > > overhead alone, never mind it doing anything, is enough to blow away > > > any benefit. Hence: > > > > > > Test3 - man load w/ptrs 35.73 nS/loop > > > Test4 - mlptrs & bzero 161.60 nS/loop > > > > > > Ouch! Of course, us old timers also see the fact that the entire > > > subroutine runs dozens of instructions in less then a microsecond and > > > say "ooooh, cool...". > > > > > > -Matt > > > > Wow! Thanks for the optimization, I hadn't considered that bzero could be > > so slow. > > > > I'm about to take off right now, I'll see if I can mock up some benchmarks > > of the overall performance of tcp_output when I get back on Monday. > > bzero seems to be optimized for large areas, perhaps it would help > malloc some if we used some alternative zero'ing function for small > allocations with M_ZERO set? That's pretty pointless; M_ZERO is _supposed_ to eventually be providing pre-zeroed memory, which should remove that bzero in the general case, anyway. -- Brian Fundakowski Feldman \ FreeBSD: The Power to Serve! / green@FreeBSD.org `------------------------------' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message