From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752885AbdFSPYe (ORCPT <rfc822;w@1wt.eu>);
        Mon, 19 Jun 2017 11:24:34 -0400
Received: from mga01.intel.com ([192.55.52.88]:1540 "EHLO mga01.intel.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1752824AbdFSPYb (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 19 Jun 2017 11:24:31 -0400
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.39,361,1493708400"; 
   d="scan'208";a="869547121"
Date: Mon, 19 Jun 2017 08:24:10 -0700
From: Andi Kleen <ak@linux.intel.com>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Kan Liang <kan.liang@intel.com>,
        Dmitri Prokhorov <Dmitry.Prohorov@intel.com>,
        Valery Cherepennikov <valery.cherepennikov@intel.com>,
        David Carrillo-Cisneros <davidcc@google.com>,
        Stephane Eranian <eranian@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/n] perf/core: addressing 4x slowdown during
 per-process profiling of STREAM benchmark on Intel Xeon Phi
Message-ID: <20170619152410.GC23705@tassilo.jf.intel.com>
References: <09226446-39b9-9bd2-d60f-b9bb947987c5@linux.intel.com>
 <20170615195618.GA8807@leverpostej>
 <07a76338-4c71-569a-d36e-7d6bcd10bd74@linux.intel.com>
 <b4b4afde-744e-b6a1-4822-b09078607cb7@linux.intel.com>
 <20170619132652.GA3894@leverpostej>
 <f3890c43-c737-4d0a-4687-c1a5adb0e542@linux.intel.com>
 <099fbd8a-9b62-faee-7eb6-07c2f94adcaa@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <099fbd8a-9b62-faee-7eb6-07c2f94adcaa@linux.intel.com>
User-Agent: Mutt/1.8.0 (2017-02-23)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> One more:

It may help if you run with KASAN enabled. That often
finds problems earlier. 

Also could use ftrace and use ftrace_dump_on_oops to 
see the sequence (but that has a lot of overhead
and sometimes hides problems)

-Andi