Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757099Ab3JJAQU (ORCPT ); Wed, 9 Oct 2013 20:16:20 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:54584 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754223Ab3JJAQT (ORCPT ); Wed, 9 Oct 2013 20:16:19 -0400 Message-ID: <5255F1A1.5090201@ti.com> Date: Wed, 9 Oct 2013 20:15:29 -0400 From: Santosh Shilimkar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: John Stultz CC: Will Deacon , Stephen Boyd , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "arm@kernel.org" , Russell King , "rob.herring@calxeda.com" , Thomas Gleixner , Daniel Lezcano Subject: Re: [PATCH] sched_clock: fix postinit no sched_clock function check References: <1380732928-13897-1-git-send-email-santosh.shilimkar@ti.com> <20131002170917.GB30298@mudshark.cambridge.arm.com> <524C5484.5000601@ti.com> <524C565C.8010709@codeaurora.org> <524C5786.2090008@ti.com> <524C5B10.20006@codeaurora.org> <20131002174841.GH30298@mudshark.cambridge.arm.com> <524C60F4.7000802@ti.com> <5255EDD6.1050401@linaro.org> In-Reply-To: <5255EDD6.1050401@linaro.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1946 Lines: 45 On Wednesday 09 October 2013 07:59 PM, John Stultz wrote: > On 10/02/2013 11:07 AM, Santosh Shilimkar wrote: >> On Wednesday 02 October 2013 01:48 PM, Will Deacon wrote: >>> On Wed, Oct 02, 2013 at 06:42:40PM +0100, Stephen Boyd wrote: >>>> On 10/02/13 10:27, Santosh Shilimkar wrote: >>>>> Really... I have not created patch out of fun. >>>>> Its broken on my keystone machine at least where the sched_clock is >>>>> falling back on jiffy based sched_clock even in presence of arch_timer >>>>> sched_clock. >>>> How is that possible? sched_clock_func is only assigned by >>>> arch/arm/kernel/arch_timer.c when the architected timer is detected and >>>> sched_clock() in kernel/time/sched_clock.c calls that function pointer >>>> unconditionally. The only way I see this happening is if the architected >>>> timer rate is zero. >>> ^^^^^^^^^^^^^^^^^^ >>> >>> *cough* CNTFRQ *cough* >>> >> :) CNTFRQ as such is fine. I think the below print mis-lead me mostly. >> >> sched_clock: ARM arch timer >56 bits at 6144kHz, resolution 162ns >> sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 4294967286ms >> >> So yes, now the subject patch actually just avoids the jiffy sched_clock() >> registration and nothing else. Even without the patch arch_timer sched_clock >> will be in use. > > Just wanted to follow up here, as I've not been paying close attention. > Is this issue then resolved, or is something still needed to be queued > for 3.12/3.13? > There is no regression as I initially thought. Patch fixes the miss-leading sched_clock print and also prevents timer to handle wrapping which is not needed. So no big deal and I don't mind if we don't apply it. Regards, Santosh -- 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/