From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [RFC][PATCH 5/3] tracing: Add smi counting to HWLAT Date: Tue, 9 Aug 2016 14:35:28 -0400 Message-ID: <20160809143528.7bd9e4a0@gandalf.local.home> References: <20160804145708.158968389@goodmis.org> <20160809140543.2e5c83b5@gandalf.local.home> <81075ecf-90c3-fdb2-59eb-defd215af2eb@redhat.com> 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 , Sebastian Andrzej Siewior , Peter Zijlstra To: Daniel Bristot de Oliveira Return-path: Received: from smtprelay0093.hostedemail.com ([216.40.44.93]:43478 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751919AbcHISfj (ORCPT ); Tue, 9 Aug 2016 14:35:39 -0400 In-Reply-To: <81075ecf-90c3-fdb2-59eb-defd215af2eb@redhat.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Tue, 9 Aug 2016 15:28:57 -0300 Daniel Bristot de Oliveira wrote: > On 08/09/2016 03:05 PM, Steven Rostedt wrote: > > If an arch supports counting of SMIs (like newer intel chips do), then it > > can implement arch_smi_count() to return the number of SMIs that were > > triggered. The hwlat detector will call this function to get the current > > number of SMIs, and then after a period, it will read that function again, > > and if there's a difference, it will record that into the sample. > > > > For example: > > > > [99] inner:13 outer:16 ts:1470352534.886878855 > > [100] inner:14 outer:18747 ts:1470352538.917966818 smi-count:2 > > [101] inner:0 outer:19162 ts:1470352539.920988709 smi-count:6 > > [102] inner:19376 outer:19276 ts:1470352540.923010578 smi-count:6 > > [103] inner:19650 outer:20665 ts:1470352541.926032469 smi-count:6 > > [104] inner:20526 outer:20680 ts:1470352542.973055312 smi-count:6 > > [105] inner:17 outer:17 ts:1470352543.990077507 > > > > Signed-off-by: Steven Rostedt > > It worked fine in a system that I can manually cause SMIs (by turning > keyboard's backlight on and off). > > Tested-by: Daniel Bristot de Oliveira Thanks! I should also add: Suggested-by: Peter Zijlstra As Peter was the one that recommended adding the arch_smi_count() function. But I can't push this yet as this would require acks from the x86 maintainers. But if there's no complaints about the rest of the patches, I could work to get that ready. -- Steve