From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www.linutronix.de ([62.245.132.108]:51272 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbbERVRe (ORCPT ); Mon, 18 May 2015 17:17:34 -0400 Date: Mon, 18 May 2015 23:17:28 +0200 From: Sebastian Andrzej Siewior To: Xander Huff Cc: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, michal.simek@xilinx.com, soren.brinkmann@xilinx.com, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rt-users@vger.kernel.org, ben.shelton@ni.com, joe.hershberger@ni.com, joshc@ni.com Subject: Re: [PATCH] iio: adc: xilinx-xadc: Convert to raw spinlock Message-ID: <20150518211728.GC4275@linutronix.de> References: <1431013090-18996-1-git-send-email-xander.huff@ni.com> <20150514171038.GG13442@linutronix.de> <55552570.5050407@ni.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <55552570.5050407@ni.com> Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org * 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? Sebastian