Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752373Ab1FWE2r (ORCPT ); Thu, 23 Jun 2011 00:28:47 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49490 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750940Ab1FWE2q (ORCPT ); Thu, 23 Jun 2011 00:28:46 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Linus Torvalds Date: Wed, 22 Jun 2011 21:28:24 -0700 Message-ID: Subject: Re: Linux 3.0-rc4 To: Andi Kleen Cc: Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1185 Lines: 30 On Wed, Jun 22, 2011 at 1:08 PM, Andi Kleen wrote: > Linus Torvalds writes: > >> and the >> conversion from spinlocks to mutexes for the anon_vma locking ended up >> causing a scalability issue that required fixing. > > FWIW it's still ~16% slower. Does that count as fixed? Well, so far I haven't really seen any suggestions on how to improve it much further. 3.0 will still be noticeably faster than 2.6.39 due to the other changes made (ie the read-ahead), so yes, the regression itself is fixed. But performance on that particular benchmark with that particular machine is clearly not optimal, in that there are known setups that would be faster still. Of course, the reason for the mutex conversion was _other_ loads, where the spinlocks had bad behavior. So it's a balancing act. And I suspect we've reached a reasonable point in that balancing, yes. Linus -- 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/