Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755976Ab0DFP3h (ORCPT ); Tue, 6 Apr 2010 11:29:37 -0400 Received: from casper.infradead.org ([85.118.1.10]:51906 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750976Ab0DFP3d (ORCPT ); Tue, 6 Apr 2010 11:29:33 -0400 Subject: Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptive spinning From: Peter Zijlstra To: Darren Hart Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Eric Dumazet , "Peter W. Morreale" , Rik van Riel , Steven Rostedt , Gregory Haskins , Sven-Thorsten Dietrich , Chris Mason , John Cooper , Chris Wright , Avi Kivity In-Reply-To: <1270499039-23728-1-git-send-email-dvhltc@us.ibm.com> References: <1270499039-23728-1-git-send-email-dvhltc@us.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 06 Apr 2010 17:29:29 +0200 Message-ID: <1270567769.20295.18.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 831 Lines: 17 On Mon, 2010-04-05 at 13:23 -0700, Darren Hart wrote: > Lastly, I should mention that these results all underperform a simple > pthread_mutex_lock()/pthread_mutex_unlock() pair. I'm looking into why but felt > I was overdue in sharing what I have to date. A test comparing this to a > sched_yield() style userspace spinlock would probably be more appropraite. This really should be able to out-perform a regular pthread_mutex_lock() we saw a significant performance gain when we added adaptive spins to the kernel mutex implementation, so I'd expect a gain on the futex one as well. -- 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/