From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755690AbYIYVNA (ORCPT ); Thu, 25 Sep 2008 17:13:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753556AbYIYVMw (ORCPT ); Thu, 25 Sep 2008 17:12:52 -0400 Received: from rv-out-0506.google.com ([209.85.198.227]:52662 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752772AbYIYVMv (ORCPT ); Thu, 25 Sep 2008 17:12:51 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type :content-transfer-encoding:content-disposition; b=oR0FbRBHHSeLdIYMtSvRSk6BvJTVuNQddYSmOWTHkEpTRsFz/rUC+psYKLuVnLwSnL y4bnbKcjvhXhPpQjz6j8h3+jaFBL4tV3GFM+kxLSQ6iAWNVWlM+4YpD/dQ1EDujoGAux KCWZtym+Ey6PHzdtnR6OE0D1kNYcuYQy4leK4= Message-ID: <3baf3d760809251412l28423a22lba5b1b57c411c87e@mail.gmail.com> Date: Thu, 25 Sep 2008 14:12:50 -0700 From: "Singaravelan Nallasellan" To: linux-kernel@vger.kernel.org Subject: Acceptable Interrupt Latency in Linux kernel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org What is the tolerable interrupt latency for the Linux interrupt handler? I need to write a driver which will require to invoke a function from other driver to read the hardware register. That function will send a message to the firmware in the some other hardware. The firmware will go into a bus to read the register and return the value. This firmware generates an interrupt of the completion of the register read. So the whole process of register read will take time to know the interrupt source. Currently I dont have the exact duration to read a single register. I am also planning to push the register read to work queue and return with IRQ handled from the ISR without knowing the hardware status.There is a potential to mis handle the interrupt. If I know the acceptable interrupt latency, It will simplify the ISR handling. Thanks