Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755133Ab3JaPRv (ORCPT ); Thu, 31 Oct 2013 11:17:51 -0400 Received: from mail-qa0-f53.google.com ([209.85.216.53]:49920 "EHLO mail-qa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754365Ab3JaPRt (ORCPT ); Thu, 31 Oct 2013 11:17:49 -0400 Date: Thu, 31 Oct 2013 11:25:55 -0400 (EDT) From: Vince Weaver To: Will Deacon cc: Vince Weaver , 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 In-Reply-To: <20131030232148.GC27743@mudshark.cambridge.arm.com> Message-ID: 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> <20131030232148.GC27743@mudshark.cambridge.arm.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323329-343091466-1383233156=:9722" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2552 Lines: 58 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-343091466-1383233156=:9722 Content-Type: TEXT/PLAIN; charset=utf-8 Content-Transfer-Encoding: 8BIT On Wed, 30 Oct 2013, Will Deacon wrote: > On Wed, Oct 30, 2013 at 02:13:11PM +0000, Vince Weaver wrote: > > 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. Probably, although Peter's been sending some "interesting" mostly untested perf patches to linux-kernel the past few days so before testing I'd rather have a patch that at least compiles cleanly. > > 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. So it might be OMAP4460/CTI specific and not related to the errata? That might be nice especially if things might work on other cortex-a9 boards. A shame about the TI people, they were often semi-responsive to my OMAP4460 questions even if it was usually just to say "ignore the documentation, that's broken, don't do that" > If you have a canned testcase for this stuff, I'm happy to run it on my > Chromebook. There's the tests/ioctl/ioctl_period test in my perf_event_tests.git tree but it's very simple. Currently it will likely just return success on current x86 Linux but fail on newish ARM and patched x86. I need to fix it to print old_behavior/new_behavior/fail I guess. I have a cortex-a15 chromebook too, but I haven't managed to get a recent kernel booting on it yet. Vince --8323329-343091466-1383233156=:9722-- -- 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/