From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262615AbVHDPpt (ORCPT ); Thu, 4 Aug 2005 11:45:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262609AbVHDPpe (ORCPT ); Thu, 4 Aug 2005 11:45:34 -0400 Received: from ms-smtp-04.nyroc.rr.com ([24.24.2.58]:64130 "EHLO ms-smtp-04.nyroc.rr.com") by vger.kernel.org with ESMTP id S262615AbVHDPow (ORCPT ); Thu, 4 Aug 2005 11:44:52 -0400 Subject: Re: [PATCH] pmtmr and PRINTK_TIME timings display From: Steven Rostedt To: Borislav Petkov Cc: lkml In-Reply-To: <200508041723.25848.petkov@uni-muenster.de> References: <200508041459.43500.petkov@uni-muenster.de> <1123161545.12009.6.camel@localhost.localdomain> <200508041723.25848.petkov@uni-muenster.de> Content-Type: text/plain; charset=UTF-8 Organization: Kihon Technologies Date: Thu, 04 Aug 2005 11:44:45 -0400 Message-Id: <1123170285.12009.18.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I get it. Actually, I wasn't very sure whether this is the right solution > since my desktop machine uses tsc timer as default while the laptop the > pmtmr. I also remember that there was a patch a while ago on lkml which > enabled a modifiable behavior for PRINTK_TIME through a /proc interface and > kernel boot option but it somehow didn't get accepted. Ok, then, since we > keep the jiffies solution across arch's, how can I force the kernel to use > tsc for printk timings so that i can see the deltas between the different > printk's instead of the jiffies_64 ns value? The Pentium-M Centrino on the > laptop evidently supports rdtsc as a msr instruction after testing with this > small inline assembly snippet: Just turn off the PM timer by disabling CONFIG_X86_PM_TIMER, then your laptop should just use the tsc timer. >>From make menuconfig: Prompt: Power Management Timer Support │ │ Defined at drivers/acpi/Kconfig:307 │ │ Depends on: !X86_VOYAGER && !X86_VISWS && !IA64_HP_SIM && (IA64 || X8 │ │ Location: │ │ -> Power management options (ACPI, APM) │ │ -> ACPI (Advanced Configuration and Power Interface) Support │ │ -> ACPI Support (ACPI [=y]) -- Steve