From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <50FEEA8F.4060509@xenomai.org> Date: Tue, 22 Jan 2013 20:37:51 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <1358809464.75419.YahooMailNeo@web140601.mail.bf1.yahoo.com> <1358883137.7479.YahooMailNeo@web140606.mail.bf1.yahoo.com> In-Reply-To: <1358883137.7479.YahooMailNeo@web140606.mail.bf1.yahoo.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] x86 Linux with xenomai and i915 graphics stall List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: A User Cc: "xenomai@xenomai.org" On 01/22/2013 08:32 PM, A User wrote: > When we run latency, we still get about 10 usec on a quiet system. > When we run glxgears and make the window size 600x600 pixels, and we > use the mouse to drag the glxgears window quickly around on the > desktop, the max latency goes to about 250 usec (with gnome-3 > fallback and compiz). That is unusual, a typical latency on x86 is under 50us (and this is a conservative bound). In order to investigate this, enable the I-pipe tracer in the kernel configuration and run latency -f. Also set the number of backtrace points to a large value, say 1000 or 10000 and post the trace here. > The option CONFIG_PCI_MSI should be disabled > > """ > > > We will keep CONFIG_PCI_MSI turned on for now, as Gilles suggests. The danger with CONFIG_PCI_MSI is that you can not mask/disable the interrupt in a real-time interrupt handler, but as long as you do not do that, you should be safe. -- Gilles.