Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 20 Nov 2002 17:02:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 20 Nov 2002 17:01:12 -0500 Received: from x35.xmailserver.org ([208.129.208.51]:10116 "EHLO x35.xmailserver.org") by vger.kernel.org with ESMTP id ; Wed, 20 Nov 2002 17:01:04 -0500 X-AuthUser: davidel@xmailserver.org Date: Wed, 20 Nov 2002 14:08:43 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@blue1.dev.mcafeelabs.com To: Jamie Lokier cc: Linux Kernel Mailing List Subject: Re: [rfc] epoll interface change and glibc bits ... In-Reply-To: <20021120220426.GB11879@bjl1.asuk.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1060 Lines: 27 On Wed, 20 Nov 2002, Jamie Lokier wrote: > Davide Libenzi wrote: > > And the lower size of the structure will help to reduce the amount of > > memory transfered to userspace. I just saw that adding the extra "obj" > > member lowered performance of about 15% with crazy tests like Ben's > > pipetest. This because it creates, on my machine, more than 400000 events > > per second, and saving memory bandwidth on such conditions is a must. With > > the "more human" http test performance are about the same. > > I'd be quite surprised if 400,000 word/sec of memory bandwidth can > explain a 15% time difference, especially considering all the other > things that are done to communicate over a pipe (wakeups etc). Jamie, they were 16 bytes * 400000, and the token passed through the pipe was 12 bytes. - Davide - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/