Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753916Ab3J3XWh (ORCPT ); Wed, 30 Oct 2013 19:22:37 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:48659 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728Ab3J3XWg (ORCPT ); Wed, 30 Oct 2013 19:22:36 -0400 Date: Wed, 30 Oct 2013 23:21:49 +0000 From: Will Deacon To: Vince Weaver Cc: Peter Zijlstra , "linux-kernel@vger.kernel.org" , Ingo Molnar , Arnaldo Carvalho de Melo , "eranian@google.com" Subject: Re: perf: PERF_EVENT_IOC_PERIOD on ARM vs everywhere else Message-ID: <20131030232148.GC27743@mudshark.cambridge.arm.com> References: <20131028085700.GB20218@mudshark.cambridge.arm.com> <20131029042810.GD22291@mudshark.cambridge.arm.com> <20131029134536.GD16117@laptop.programming.kicks-ass.net> <20131030095615.GG16117@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1399 Lines: 33 On Wed, Oct 30, 2013 at 02:13:11PM +0000, Vince Weaver wrote: > On Wed, 30 Oct 2013, Peter Zijlstra wrote: > > The below code should deal with both cases I think -- completely > > untested. > > Uncompiled too I guess? > > kernel/events/core.c: In function ‘perf_event_period’: > kernel/events/core.c:3531: error: invalid type argument of ‘->’ (have ‘local64_t’) > make[3]: *** [kernel/events/core.o] Error 1 That's trivial to fix. > I also won't be able to test the ARM change, as my pandaboard won't boot > with recent kernels (can't find the MMC root filesystem) and I haven't had > time to track down why. Also even on a simple period changing test it > often fails due to lost interrupts (the Cortex-A9 lost interrupt errata?). The omap guys like trying to blame the A9 erratum for that (which doesn't even affect the cycle counter), but the reality is that the CTI never worked reliably with mainline, and now there are no developers working on that after the TI layoffs. I don't see the state of Pandaboard support improving over time. If you have a canned testcase for this stuff, I'm happy to run it on my Chromebook. Will -- 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/