From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH] iio: adc: xilinx-xadc: Convert to raw spinlock Date: Sun, 07 Jun 2015 16:29:03 +0100 Message-ID: <5574633F.7090004@kernel.org> References: <1431013090-18996-1-git-send-email-xander.huff@ni.com> <20150514171038.GG13442@linutronix.de> <55552570.5050407@ni.com> <20150518211728.GC4275@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: knaack.h-Mmb7MZpHnFY@public.gmane.org, lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org, pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org, michal.simek-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org, soren.brinkmann-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-rt-users-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ben.shelton-acOepvfBmUk@public.gmane.org, joe.hershberger-acOepvfBmUk@public.gmane.org, joshc-acOepvfBmUk@public.gmane.org To: Sebastian Andrzej Siewior , Xander Huff Return-path: In-Reply-To: <20150518211728.GC4275-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rt-users.vger.kernel.org On 18/05/15 22:17, Sebastian Andrzej Siewior wrote: > * Xander Huff | 2015-05-14 17:45:04 [-0500]: > >> With no other processes running, I got the following results after a >> couple of hours on one of our devices: >> >> admin@Xander-roboRIO:~# cyclictest -S -m -p 98 >> # /dev/cpu_dma_latency set to 0us >> policy: fifo: loadavg: 0.01 0.07 0.12 1/176 1473 >> >> T: 0 ( 1373) P:98 I:1000 C:6503872 Min: 9 Act: 13 Avg: 13 Max: 51 >> T: 1 ( 1374) P:98 I:1500 C:4335914 Min: 9 Act: 12 Avg: 13 Max: 49 >> >> With a VI reading all default handles (raw, offset, scale, >> sampling_frequency) in /sys/bus/iio/devices/iio:device0 constantly in >> a while loop, I got the following results after a couple hours on the >> same device: >> >> admin@Xander-roboRIO:~# cyclictest -S -m -p 98 >> # /dev/cpu_dma_latency set to 0us >> policy: fifo: loadavg: 6.93 7.30 7.47 3/182 1530 >> >> T: 0 ( 1487) P:98 I:1000 C:4497008 Min: 11 Act: 20 Avg: 21 Max: 69 >> T: 1 ( 1488) P:98 I:1500 C:2998005 Min: 11 Act: 20 Avg: 22 Max: 59 > > So there is an increase. And there is even a for-loop and I don't know > how deep it is nested. Anyway, do you think it is worth it or would it > be better to get rid of the raw-locks and simply push everything into > threaded context? > Certainly seems likely to be a better way forward to me but I don't really mind either way. J