From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754529AbcKUWGP (ORCPT ); Mon, 21 Nov 2016 17:06:15 -0500 Received: from mail-pg0-f54.google.com ([74.125.83.54]:32787 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753763AbcKUWGN (ORCPT ); Mon, 21 Nov 2016 17:06:13 -0500 From: Joel Fernandes To: linux-kernel@vger.kernel.org Cc: Joel Fernandes , Steven Rostedt , Thomas Gleixner , John Stultz , Ingo Molnar Subject: [PATCH 0/2] Introduce a fast boot clock and add it as trace clock Date: Mon, 21 Nov 2016 14:04:55 -0800 Message-Id: <1479765897-29992-1-git-send-email-joelaf@google.com> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently no trace clock can account for suspend time, using monotonic during tracing in the suspend path means the trace times wont be advaced. Using the boot clock with ktime_get_with_offset is not an option due to live locking concerns in NMI context as suggested by Thomas [1]. These patches add a fast boot clock based on fast monotonic clock and adds a trace clock based on it which solves both these issues. Changes since RFC: - Moved the ktime_t offsets to the end of tk_fast - use unlikely to optimize for the monotonic case [1] https://lkml.org/lkml/2016/11/20/75 Joel Fernandes (2): timekeeping: Introduce a fast boot clock derived from fast monotonic clock trace: Add an option for boot clock as trace clock kernel/time/timekeeping.c | 36 ++++++++++++++++++++++++++++++------ kernel/trace/trace.c | 1 + 2 files changed, 31 insertions(+), 6 deletions(-) Cc: Steven Rostedt Cc: Thomas Gleixner Cc: John Stultz Cc: Ingo Molnar -- 2.8.0.rc3.226.g39d4020