From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4F735716.4020508@domain.hid> Date: Wed, 28 Mar 2012 14:23:18 -0400 From: Makarand Pradhan MIME-Version: 1.0 References: <4F7333E7.7030608@domain.hid> <4F7339A8.6060701@domain.hid> In-Reply-To: <4F7339A8.6060701@domain.hid> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Interrupt latency greater than 250ms. Question. List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe Gerum Cc: "xenomai@xenomai.org" Hi Philippe, On 28/03/12 12:17 PM, Philippe Gerum wrote: > The log says your code wants to control when the IRQ is enabled again, > by calling rt_intr_enable() from userland. I guess you are setting > I_NOAUTOENA too. Correct? That is correct. I_NOAUTOENA is used in rt_intr_create. Otherwise the level trigerred interrupt will not allow the userland processing of the int. The userland handler is very small and it unconditionally rt_intr_enables the intr. Testing indicates that the interrupt is always enabled from user space within 250 usec after kernel gets the interrupt. I have noted that unless I see "#end 0x0000002b" and a hit to the ipic_unmask_irq, the next interrupt is not processed. And this is getting delayed once in a while which causes a delay in processing the next interrupt. So the sequence of events leading to the problem is: 1. Get interrupt: #begin 0x0000002b noted in ipipe trace 2. Intr enabled from user space. Always happens roughly within 250usec. 3. #end 0x0000002b noted in ipipe trace where the int is unmasked by ipipe. When I see the problem, step 3 is delayed. I am trying to capture a trace where the begin, int enable and end are captured. Your thoughts on what might cause this delay would be appreciated. Rgds, Mak. -- ___________________________________________________________________________ NOTICE OF CONFIDENTIALITY: This e-mail and any attachments may contain confidential and privileged information. If you are not the intended recipient, please notify the sender immediately by return e-mail and delete this e-mail and any copies. Any dissemination or use of this information by a person other than the intended recipient is unauthorized and may be illegal. _____________________________________________________________________