From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 18 Dec 2014 12:08:58 +0100 From: Gilles Chanteperdrix Message-ID: <20141218110858.GL2012@hermes.click-hack.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Xenomai] Latency spikes List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Herzog Cc: xenomai@xenomai.org On Thu, Dec 18, 2014 at 09:39:31AM +0100, Alexander Herzog wrote: > Hi all, > > We see latency spikes on our xenomai install whenever we open a > window, take a screenshot or perform similar actions. The spikes > are especially high (~2000) the moment an opengl window is opened > (e.g. glxgears). Outside of these events (e.g. once a window is > open) the latencies seem to be stable. The issue remains even, if > we switch graphics cards (and graphics drivers) from a nvidia to a > radeon card. For nvidia, have you tried the "nouveau" driver? > > We are running Xenomai 2.6.3 on an Intel Xeon E5-2687W v3 310GHz > processor and Ubuntu 12.04 (linux kernel version 3.8.13). I went > through the troubleshooting section and made sure that the > deprecated config flags (CONFIG_CPU_FREQ, CONFIG_CPU_IDLE, > CONFIG_KGDB, CONFIG_CONTEXT_TRACKING_FORCE) are disabled. We see > the warning 'SMI-enabled chipset found, but SMI workaround > disabled', but passing 'xenomai.smi=-1' to the kernel does not fix > our issue. As explained in the following document: https://xenomai.org//2014/06/dealing-with-x86-smi-troubles/ Passing xenomai.smi=-1 disables the SMI message. You should try passing xenomai.smi=1 if you want to enable the SMI workaround (with caution, please read the document) > > I would be thankful for any hint on how I could further debug this issue. The only generic advices we have for this case are: - use an intel processor with on board graphic chip, with a recent version of Xenomai and I-pipe patches (some things have been fixed in this area, I believe since xenomai 2.6.3) - as explained in the troubleshooting guide, https://xenomai.org/troubleshooting-a-dual-kernel-configuration/#the_latency_test_shows_high_latencies you can disable hardware acceleration -- Gilles.