From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756301AbaIZXbX (ORCPT ); Fri, 26 Sep 2014 19:31:23 -0400 Received: from mga01.intel.com ([192.55.52.88]:37102 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755940AbaIZXbV (ORCPT ); Fri, 26 Sep 2014 19:31:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,606,1406617200"; d="scan'208";a="597491069" From: Andi Kleen To: peterz@infradead.org Cc: dave@sr71.net, linux-kernel@vger.kernel.org, mingo@kernel.org, eranian@google.com, x86@kernel.org Subject: Optimize backtrace code for perf PMI handler. Date: Fri, 26 Sep 2014 16:31:15 -0700 Message-Id: <1411774277-4198-1-git-send-email-andi@firstfloor.org> X-Mailer: git-send-email 1.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While doing perf record -g I regularly exceed the time quote for the NMI: This leads to perf shortening the period, which causes various problems. This patchkit optimizes two sources of longer latencies in the NMI backtrace code. There's probably more work needed to fix other sources of latencies too. -Andi