From mboxrd@z Thu Jan 1 00:00:00 1970 From: Siarhei Siamashka Subject: Re: get_irq_regs() from soft IRQ Date: Mon, 29 Jun 2009 19:36:57 +0300 Message-ID: <200906291936.57703.siarhei.siamashka@nokia.com> References: <200906291631.19562.jpihet@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200906291631.19562.jpihet@mvista.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: oprofile-list-bounces@lists.sourceforge.net To: ext Jean Pihet Cc: "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.arm.linux.org.uk" , "oprofile-list@lists.sourceforge.net" List-Id: linux-omap@vger.kernel.org On Monday 29 June 2009 17:31:18 ext Jean Pihet wrote: > Hi, > > I am trying to get the latest IRQ registers from a timer or a work queue > but I am running into problems: > - get_irq_regs() returns NULL in some cases, so it is unsuable and even > causes crash when trying to get the registers values from the returned ptr > - I never get user space registers, only kernel > > The use case is that the performance unit (PMNC) of the Cortex A8 has some > serious bug, in short the performance counters overflow IRQ is to be > avoided. The solution I am implementing is to read and reset the counters > from a work queue that is triggered by a timer. Regarding this oprofile related part. I wonder how you can get oprofile working properly (providing non-bogus results) without performance counters overflow IRQ generation? Are you trying to implement (in a clean way) something similar to http://marc.info/?l=oprofile-list&m=123688347009580&w=2 Or is it going to be a different workaround? -- Best regards, Siarhei Siamashka ------------------------------------------------------------------------------