Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755524Ab3JBSIi (ORCPT ); Wed, 2 Oct 2013 14:08:38 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:34125 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754474Ab3JBSIh (ORCPT ); Wed, 2 Oct 2013 14:08:37 -0400 Message-ID: <524C60F4.7000802@ti.com> Date: Wed, 2 Oct 2013 14:07:48 -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: Will Deacon CC: Stephen Boyd , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "arm@kernel.org" , John Stultz , 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> In-Reply-To: <20131002174841.GH30298@mudshark.cambridge.arm.com> 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: 1402 Lines: 33 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. 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/