From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754091Ab1BBM20 (ORCPT ); Wed, 2 Feb 2011 07:28:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:19273 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753617Ab1BBM2Z (ORCPT ); Wed, 2 Feb 2011 07:28:25 -0500 From: Jiri Olsa To: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, fweisbec@gmail.com, Jiri Olsa Subject: [PATCH] trace: adding unstable sched clock note to the warning Date: Wed, 2 Feb 2011 13:28:18 +0100 Message-Id: <1296649698-6003-1-git-send-email-jolsa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hi, warning "Delta way too big" warning might appear on a system with unstable shed clock right after the system is resumed and tracing was enabled during the suspend. Since it's not realy bug, and the unstable sched clock is working fast and reliable otherwise, Steven suggested to keep using the sched clock in any case and just to make note in the warning itself. wbr, jirka Signed-off-by: Jiri Olsa --- kernel/trace/ring_buffer.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index bd1c35a..7739893 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2163,10 +2163,14 @@ rb_reserve_next_event(struct ring_buffer *buffer, delta = diff; if (unlikely(test_time_stamp(delta))) { WARN_ONCE(delta > (1ULL << 59), - KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n", + KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s", (unsigned long long)delta, (unsigned long long)ts, - (unsigned long long)cpu_buffer->write_stamp); + (unsigned long long)cpu_buffer->write_stamp, + sched_clock_stable ? "" : + "If you just came from a suspend/resume,\n" + "please switch to the trace global clock:\n" + " echo global > /sys/kernel/debug/tracing/trace_clock\n"); add_timestamp = 1; } }