Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757890Ab1E1Dir (ORCPT ); Fri, 27 May 2011 23:38:47 -0400 Received: from jaguar.mail.utk.edu ([160.36.0.84]:34404 "EHLO jaguar.mail.utk.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755362Ab1E1Diq (ORCPT ); Fri, 27 May 2011 23:38:46 -0400 Date: Fri, 27 May 2011 23:38:30 -0400 (EDT) From: Vince Weaver To: Peter Zijlstra cc: linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org, acme@redhat.com Subject: Re: perf: regression with PERF_EVENT_IOC_REFRESH In-Reply-To: <1306233036.2497.15.camel@laptop> Message-ID: References: <1306182141.2497.5.camel@laptop> <1306233036.2497.15.camel@laptop> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1024 Lines: 28 On Tue, 24 May 2011, Peter Zijlstra wrote: > > This is very clear abuse of the API and I'm not really inclined to fix > it, in fact, I'd be tempted to add an additional test to verify the > argument to REFRESH > 0. on that note (and while trying to document exactly what the ioctls do) it seems that a PERF_EVENT_IOC_REFRESH with an argument of anything higher than one does not work on kernels 2.6.36 and newer. The behavior acts as if 1 was passed, even if you pass in, say, 3. Is it worth bisecting this, or has this become the new official behavior since no one noticed until now? To reproduce you can grab my tests from here: http://web.eecs.utk.edu/~vweaver1/projects/perf-events/validation.html and run the ./validation/simple_overflow_leader test Vince -- 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/