Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752051Ab3F3PK5 (ORCPT ); Sun, 30 Jun 2013 11:10:57 -0400 Received: from mail-we0-f169.google.com ([74.125.82.169]:44175 "EHLO mail-we0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751135Ab3F3PK4 (ORCPT ); Sun, 30 Jun 2013 11:10:56 -0400 MIME-Version: 1.0 In-Reply-To: References: <1372511678-2726-1-git-send-email-kerolasa@iki.fi> <8761wxxafc.fsf@xmission.com> From: Kay Sievers Date: Sun, 30 Jun 2013 17:10:34 +0200 Message-ID: Subject: Re: [PATCH] proc: make high precision system boot time available To: kerolasa@gmail.com Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, Karel Zak , Lennart Poettering 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: 1128 Lines: 26 On Sat, Jun 29, 2013 at 10:53 PM, Sami Kerola wrote: > BTW having a way to measure effect of suspend/resume could lead to a > way to fix time time distortion. > Perhaps there is better alternative to fix user space programs. > Unfortunately I do not have either knowledge, or imagination, to come > up with any. Fix hints, ideas, and other proposal are most welcome. Stuff should just use: clock_gettime(CLOCK_BOOTTIME, &ts); to get the time in better resolution, and with suspend time taken into account? As a general note, the kmsg/printk() time in the raw kernel log is the time of the CPU it runs on, especially during early init this time might not be in sync across CPUs and stuff jumps event in the very same stream on events from the kernel itself: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/kernel/sched/clock.c#n329 Kay -- 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/