From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f174.google.com (mail-pd0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id 6C0CE6B0031 for ; Wed, 29 Jan 2014 03:30:27 -0500 (EST) Received: by mail-pd0-f174.google.com with SMTP id z10so1424608pdj.19 for ; Wed, 29 Jan 2014 00:30:27 -0800 (PST) Received: from mail-pa0-x22f.google.com (mail-pa0-x22f.google.com [2607:f8b0:400e:c03::22f]) by mx.google.com with ESMTPS id mj6si1677121pab.188.2014.01.29.00.30.26 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 29 Jan 2014 00:30:26 -0800 (PST) Received: by mail-pa0-f47.google.com with SMTP id kp14so1478170pab.6 for ; Wed, 29 Jan 2014 00:30:26 -0800 (PST) Date: Wed, 29 Jan 2014 00:30:19 -0800 (PST) From: David Rientjes Subject: Re: [PATCH] mm: slub: fix page->_count corruption (again) In-Reply-To: <52E842CF.7090102@sr71.net> Message-ID: References: <20140128231722.E7387E6B@viggo.jf.intel.com> <20140128152956.d5659f56ae279856731a1ac5@linux-foundation.org> <52E842CF.7090102@sr71.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cl@linux-foundation.org, penberg@kernel.org, mpm@selenic.com, pshelar@nicira.com, Wu Fengguang On Tue, 28 Jan 2014, Dave Hansen wrote: > It has measurable performance benefits, and the benefits go up as the > cost of en/disabling interrupts goes up (like if it takes you a hypercall). > > Fengguang, could you run a set of tests for the top patch in this branch > to see if we'd be giving much up by axing the code? > > https://github.com/hansendc/linux/tree/slub-nocmpxchg-for-Fengguang-20140128 > > I was talking with one of the distros about turning it off as well. > They mentioned that they saw a few performance regressions when it was > turned off. I'll share details when I get them. > FWIW, I've compared netperf TCP_RR on all machine types I have available with and without cmpxchg_double and I've never measured a regression. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org