From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [RFC V2 1/2] irq: Add a framework to measure interrupt timings Date: Thu, 21 Jan 2016 14:52:31 +0100 (CET) Message-ID: References: <1453305636-22156-1-git-send-email-daniel.lezcano@linaro.org> <1453305636-22156-2-git-send-email-daniel.lezcano@linaro.org> <20160120190718.GS6357@twins.programming.kicks-ass.net> <56A0A9E3.2070306@linaro.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from www.linutronix.de ([62.245.132.108]:38235 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759002AbcAUNxd (ORCPT ); Thu, 21 Jan 2016 08:53:33 -0500 In-Reply-To: <56A0A9E3.2070306@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Daniel Lezcano Cc: Peter Zijlstra , rafael@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, nicolas.pitre@linaro.org, vincent.guittot@linaro.org On Thu, 21 Jan 2016, Daniel Lezcano wrote: > On 01/20/2016 08:57 PM, Thomas Gleixner wrote: > > That and we don't want to call it for each handler which returned handled. > > The > > called code would do two samples in a row for the same interrupt in case of > > two shared handlers which get raised at the same time. Not very likely, but > > possible. > > Actually, the handle passes dev_id in order to let the irqtimings to sort out > a shared interrupt and prevent double sampling. In other words, for shared > interrupts, statistics should be per t-uple(irq , dev_id) but that is > something I did not implemented ATM. So my comment about double sampling applies. > IMO, the handler is at the right place. The prediction code does not take care > of the shared interrupts yet. > > I tried to find a platform with shared interrupts in the ones I have available > around me but I did not find any. Are the shared interrupts something used > nowadays or coming from legacy hardware ? What is the priority to handle the > shared interrupts in the prediction code ? And why would that thing care about shared interruts at all? It's a legacy burden and I really don't see a reason why that new thing which is targeted on modern hardware should deal with them. Just treat them as a single interrupt for now and be done with it. Thanks, tglx