Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752748AbdGXFqP (ORCPT ); Mon, 24 Jul 2017 01:46:15 -0400 Received: from mga11.intel.com ([192.55.52.93]:13279 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751616AbdGXFqI (ORCPT ); Mon, 24 Jul 2017 01:46:08 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,405,1496127600"; d="scan'208";a="130256082" From: "Huang\, Ying" To: "Steven Rostedt \(Red Hat\)" Cc: Mengyang Liu , "Brandt\, Todd E" , "linux-kernel\@vger.kernel.org" Subject: Is it possible to use ftrace to measure secondary CPU bootup time Date: Mon, 24 Jul 2017 13:46:07 +0800 Message-ID: <874lu2fkv4.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 427 Lines: 11 Hi, Steven, We are working on parallelizing secondary CPU bootup. So we need to measure the bootup time of secondary CPU, that is, measure time spent in smp_init() and its callees. But we found that ftrace now doesn't support measure time spent in smp_init() because it is called too early (before core_initcall()?). So, do you think it is possible to use ftrace to measure secondary CPU bootup time? Thanks, Huang, Ying