From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754463AbcETJAn (ORCPT ); Fri, 20 May 2016 05:00:43 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:59778 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752075AbcETJAl (ORCPT ); Fri, 20 May 2016 05:00:41 -0400 Date: Fri, 20 May 2016 11:00:34 +0200 From: Peter Zijlstra To: Davidlohr Bueso Cc: manfred@colorfullife.com, Waiman.Long@hpe.com, mingo@kernel.org, torvalds@linux-foundation.org, ggherdovich@suse.com, mgorman@techsingularity.net, linux-kernel@vger.kernel.org Subject: Re: sem_lock() vs qspinlocks Message-ID: <20160520090034.GO3205@twins.programming.kicks-ass.net> References: <20160520053926.GC31084@linux-uzut.site> <20160520083008.GD3193@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160520083008.GD3193@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 20, 2016 at 10:30:08AM +0200, Peter Zijlstra wrote: > On Thu, May 19, 2016 at 10:39:26PM -0700, Davidlohr Bueso wrote: > > Specifically > > for the 'cascade_cond' and 'cascade_flock' programs, which exhibit hangs in libc's > > semop() blocked waiting for zero. > > OK; so I've been running: > > while :; do > bin/cascade_cond -E -C 200 -L -S -W -T 200 -I 2000000 ; > bin/cascade_flock -E -C 200 -L -S -W -P 200 -I 5000000 ; > done > > for a few minutes now and its not stuck and my machine didn't splat. > > Am I not doing it right? Hooray, it went *bang*.. OK, lemme have a harder look at this semaphore code.