From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [RFC][PATCH 4/3] tracing: Add NMI tracing in hwlat detector Date: Fri, 5 Aug 2016 12:17:06 -0400 Message-ID: <20160805121706.2766ea1a@gandalf.local.home> References: <20160804145708.158968389@goodmis.org> <20160804125618.6db9b5b3@gandalf.local.home> <20160804131645.1ba3244a@gandalf.local.home> <20160805143555.GB21312@linutronix.de> <20160805105207.16e26a41@gandalf.local.home> <903851a5-68a6-acaa-6604-c63f6aa11b4c@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Ingo Molnar , Andrew Morton , Clark Williams , Thomas Gleixner , Jon Masters , Daniel Wagner , Carsten Emde To: Sebastian Andrzej Siewior Return-path: Received: from smtprelay0227.hostedemail.com ([216.40.44.227]:36830 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935016AbcHEQRN (ORCPT ); Fri, 5 Aug 2016 12:17:13 -0400 In-Reply-To: <903851a5-68a6-acaa-6604-c63f6aa11b4c@linutronix.de> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Fri, 5 Aug 2016 17:40:43 +0200 Sebastian Andrzej Siewior wrote: > > Ah, this is when we have GENERIC_SCHED_CLOCK, which would break tracing > > if any arch that has this also has NMIs. Probably need to look at arm64. > > arm64 should use the generic code as they don't provide sched_clock() > (and I doubt they go for the weak jiffy version). And I'm guessing that arm64 supports NMIs. Is there no NMI safe clock? I probably need to look at the tracing code. Because you can have the same issue while tracing in an NMI as well. -- Steve