Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751696AbWHXUDl (ORCPT ); Thu, 24 Aug 2006 16:03:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751691AbWHXUDl (ORCPT ); Thu, 24 Aug 2006 16:03:41 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:48076 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1751692AbWHXUDk (ORCPT ); Thu, 24 Aug 2006 16:03:40 -0400 Date: Thu, 24 Aug 2006 21:03:22 +0100 From: Christoph Hellwig To: Evgeniy Polyakov Cc: lkml , David Miller , Ulrich Drepper , Andrew Morton , netdev , Zach Brown , Christoph Hellwig Subject: Re: [take13 1/3] kevent: Core files. Message-ID: <20060824200322.GA19533@infradead.org> Mail-Followup-To: Christoph Hellwig , Evgeniy Polyakov , lkml , David Miller , Ulrich Drepper , Andrew Morton , netdev , Zach Brown References: <11563322941645@2ka.mipt.ru> <11563322971212@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11563322971212@2ka.mipt.ru> User-Agent: Mutt/1.4.2.1i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 773 Lines: 15 One question on the implementation of kevent_user_ctl_modify/ kevent_user_ctl_remove/kevent_user_ctl_add: What benchmarks did you do to add the separate 'fastpath' with the single onstack ukevent structure if there are three or less events? I can't believe this actually helps in practice for various reasons: - you add quite a lot of icache footprint by duplicating all this code - kmalloc is really fast - two or three small copy_from/to_user calls are quite a bit slower than one that covers the size of all of them. - 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/