From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: [PATCH] ACPI: Add debugfs support for ACPICA boot time measurement. Date: Thu, 08 Nov 2012 01:08:54 -0500 Message-ID: <509B4C76.7000105@kernel.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-vb0-f46.google.com ([209.85.212.46]:57527 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881Ab2KHGI5 (ORCPT ); Thu, 8 Nov 2012 01:08:57 -0500 Received: by mail-vb0-f46.google.com with SMTP id ff1so2359120vbb.19 for ; Wed, 07 Nov 2012 22:08:56 -0800 (PST) In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lv Zheng Cc: Len Brown , Rafael J Wysocki , linux-acpi@vger.kernel.org On 11/07/2012 08:49 PM, Lv Zheng wrote: > ACPICA defines the following initialization steps that must be called to > make ACPICA functional: > 1. acpi_initialize_tables > 2. acpi_initialize_subsystem > 3. acpi_load_tables > 4. acpi_enable_subsystem > 5. acpi_initialize_objects > 6. OSPM specific bus scanning > 7. acpi_update_all_gpes > This patch allows developers to check the execution time of such bootup > steps through /sys/kernel/debug/acpi/acpica_init_time. > > The ACPICA 20121018 release measurement result is as follows: > ======================================== > 0.000000 acpi_initialize_tables > 0.000034 acpi_initialize_subsystem > 0.004822 acpi_load_tables > 0.003351 acpi_enable_subsystem > 0.003204 acpi_initialize_objects > 0.045082 acpi_bus_scan > 0.000023 acpi_bus_scan_fixed > 0.000017 acpi_update_all_gpes > ======================================== > The left column is the execution time in timeval (sec.usec) format. > The right column indicates the name of the initialization step. As you've identified that 80% of the ACPI startup time goes to acpi_bus_scan(), have you identified any ways to make acpi_bus_scan() faster? Do these numbers vary greatly when run on different machines? thanks, -Len Brown, Intel Open Source Technology Center