Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753221Ab3GHU4k (ORCPT ); Mon, 8 Jul 2013 16:56:40 -0400 Received: from mail-ob0-f178.google.com ([209.85.214.178]:33839 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753072Ab3GHU4j (ORCPT ); Mon, 8 Jul 2013 16:56:39 -0400 MIME-Version: 1.0 In-Reply-To: <20130708205401.GG5643@tassilo.jf.intel.com> References: <20130704223010.GA30625@quad> <51DACE08.5030109@intel.com> <51DB1B75.8060303@intel.com> <51DB2271.1010009@sr71.net> <20130708205401.GG5643@tassilo.jf.intel.com> Date: Mon, 8 Jul 2013 22:56:38 +0200 Message-ID: Subject: Re: [PATCH] perf: fix interrupt handler timing harness From: Stephane Eranian To: Andi Kleen Cc: Dave Hansen , Dave Hansen , LKML , Peter Zijlstra , "mingo@elte.hu" , dave.hansen@linux.jf.intel.com, Jiri Olsa Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 825 Lines: 16 On Mon, Jul 8, 2013 at 10:54 PM, Andi Kleen wrote: >> I did a quite a bit of ftracing to look for spots inside the handler >> which were taking large amounts of time. There were none. The >> execution time was spread very evenly over the entire nmi handler. It >> didn't appear to be any individual hot cachelines or doing something >> silly like sitting in a loop handling lots of PMU events. > > In some cases callgraphs seemed to be quite expensive (large fraction > of the handler time) > In my case, I am not doing callgraphs, just regular cycles. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/