Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753375AbaFMQNi (ORCPT ); Fri, 13 Jun 2014 12:13:38 -0400 Received: from mail-wg0-f41.google.com ([74.125.82.41]:33736 "EHLO mail-wg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752955AbaFMQNh (ORCPT ); Fri, 13 Jun 2014 12:13:37 -0400 MIME-Version: 1.0 In-Reply-To: References: <1402603992-12466-1-git-send-email-davidriley@chromium.org> <1402603992-12466-2-git-send-email-davidriley@chromium.org> Date: Fri, 13 Jun 2014 09:13:35 -0700 Message-ID: Subject: Re: [PATCH v3 1/2] kernel: time: Add udelay_test module to validate udelay From: David Riley To: John Stultz Cc: Thomas Gleixner , Doug Anderson , lkml Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 13, 2014 at 9:06 AM, John Stultz wrote: > On Thu, Jun 12, 2014 at 1:13 PM, David Riley wrote: >> Create a module that allows udelay() to be executed to ensure that >> it is delaying at least as long as requested (with a little bit of >> error allowed). >> >> There are some configurations which don't have reliably udelay >> due to using a loop delay with cpufreq changes which should use >> a counter time based delay instead. This test aims to identify >> those configurations where timing is unreliable. >> >> Signed-off-by: David Riley >> --- >> kernel/time/Kconfig | 7 ++ >> kernel/time/Makefile | 1 + >> kernel/time/udelay_test.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 178 insertions(+) >> create mode 100644 kernel/time/udelay_test.c >> >> diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig >> index f448513..c6af048 100644 >> --- a/kernel/time/Kconfig >> +++ b/kernel/time/Kconfig >> @@ -202,3 +202,10 @@ config HIGH_RES_TIMERS >> >> endmenu >> endif >> + >> +config UDELAY_TEST >> + tristate "udelay test driver" >> + default n >> + help >> + This builds the "udelay_test" module that helps to make sure >> + that udelay() is working properly. > > > Thanks for resubmitting! So I've queued this for my testing. > > My only thoughts playing with it now, is that the Kconfig entry is > just in an awkward spot. There isn't really a udelay, or really > general timekeeping specific area in the menus, so it just shows up in > "General Setup" between the "Timer Subsystem" and "Cpu/task time.." > submenus. > > I suspect this would be better added in lib/Kconfig.debug near > TEST_MODULE. Any objections to me changing that? > > Also I'd probably rename the config option to TEST_UDELAY, as well as > tweak the option string to be more consistent with those similar test > driver options. Hi John, I'm okay with those changes. Do you want me to resubmit or will you just make the changes locally? Thanks Dave > > thanks > -john -- 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/