Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755914AbZFBO5U (ORCPT ); Tue, 2 Jun 2009 10:57:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750948AbZFBO5F (ORCPT ); Tue, 2 Jun 2009 10:57:05 -0400 Received: from mail-qy0-f104.google.com ([209.85.221.104]:61252 "EHLO mail-qy0-f104.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751921AbZFBO5E convert rfc822-to-8bit (ORCPT ); Tue, 2 Jun 2009 10:57:04 -0400 X-Greylist: delayed 453 seconds by postgrey-1.27 at vger.kernel.org; Tue, 02 Jun 2009 10:57:04 EDT DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=EqnzxenEe1HG9giKi5TKDdxtXnIE05z+g2RjYYCIq1+8TyPznugEdRYQ9FByL7WLdP TM0H/idyhw72W0L9kYJwivrwaYrFgm45r9RooeUJ9gQcMD2Pm+ZoxXr7+hCumkiBm5KB CYA0iJLvP4+ys8VY/ylV8vTloKtqhVHGBZq6M= MIME-Version: 1.0 In-Reply-To: <20090602141802.GC3914@think> References: <4A0B62F7.5030802@goop.org> <20090525091527.GA7535@elte.hu> <4A1C3805.7060404@goop.org> <20090528061702.GB6920@wotan.suse.de> <20090530102330.GC16913@elte.hu> <20090602141802.GC3914@think> Date: Tue, 2 Jun 2009 07:49:32 -0700 Message-ID: Subject: Re: [benchmark] 1% performance overhead of paravirt_ops on native kernels From: Ulrich Drepper To: Chris Mason , Ingo Molnar , Nick Piggin , Jeremy Fitzhardinge , "H. Peter Anvin" , Thomas Gleixner , Linux Kernel Mailing List , Andrew Morton , Linus Torvalds , Peter Zijlstra , Avi Kivity , Arjan van de Ven Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1303 Lines: 23 On Tue, Jun 2, 2009 at 7:18 AM, Chris Mason wrote: > I'm not suggesting we should take broken code, or that we should lower > standards just for xen.  But, expecting the xen developers to fix the 1% > hit on a very specific micro-benchmark is not a way to promote new > projects for the kernel, and it isn't a good way to convince people to > do continued development in mainline instead of in private trees. It's not a new project which needs to be treated with kid's gloves. And one be sure that once the code is in the tree those interested parties will not be as strongly motivated to fix any problem like this. Ingo pointed to a way which doesn't negatively impact the performance of the Xen kernel and reduces the overhead (dynamic patching). Just get started on this (and general cleanup) and this whole argument will go away. I find it ridiculous to use the "but it's used" argument to try to force the code into the kernel. By this argument you can say the same about crap like ndiswrapper and similarly harmful code. -- 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/