LKML Archive on
help / color / mirror / Atom feed
From: Steven Rostedt <>
To: Chris Wilson <>
Subject: Re: [PATCH v2 1/2] trace: Default to using trace_global_clock if sched_clock is unstable
Date: Mon, 2 Apr 2018 11:17:36 -0400	[thread overview]
Message-ID: <20180402111736.763c861e@gandalf.local.home> (raw)
In-Reply-To: <>

On Fri, 30 Mar 2018 16:01:31 +0100
Chris Wilson <> wrote:

> Across suspend, we may see a very large drift in timestamps if the sched
> clock is unstable, prompting the global trace's ringbuffer code to warn
> and suggest switching to the global clock. Preempt this request by
> detecting when the sched clock is unstable (determined during
> late_initcall) and automatically switching the default clock over to
> trace_global_clock.
> This should prevent requiring user interaction to resolve warnings such
> as:
>     Delta way too big! 18446743856563626466 ts=18446744054496180323 write stamp = 197932553857
>     If you just came from a suspend/resume,
>     please switch to the trace global clock:
>     echo global > /sys/kernel/debug/tracing/trace_clock
> Signed-off-by: Chris Wilson <>
> Cc: Steven Rostedt (VMware) <>
> ---
> v2: Tell the user what's happening and what they can do to correct it.

Thanks, I pulled them in. I'll start testing them before I post to git.

-- Steve

  parent reply	other threads:[~2018-04-02 15:17 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 15:01 Chris Wilson
2018-03-30 15:01 ` [PATCH v2 2/2] trace: Mention trace_clock=global when warning about unstable clocks Chris Wilson
2018-04-02 15:17 ` Steven Rostedt [this message]
2018-04-04 20:46 ` [PATCH v2 1/2] trace: Default to using trace_global_clock if sched_clock is unstable Chris Wilson
2018-04-04 20:51 ` [PATCH v3] " Chris Wilson
2018-04-04 20:56   ` Steven Rostedt
2018-04-04 21:24     ` [PATCH] trace: Fixup logic inversion on setting trace_global_clock defaults Chris Wilson
2018-04-05 11:48       ` Steven Rostedt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180402111736.763c861e@gandalf.local.home \ \ \ \ \
    --subject='Re: [PATCH v2 1/2] trace: Default to using trace_global_clock if sched_clock is unstable' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).