linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sodagudi Prasad <psodagud@codeaurora.org>,
	gregkh@linuxfoundation.org, john.stultz@linaro.org,
	chang-an.chen@mediatek.com, mingo@kernel.org, pmladek@suse.com,
	sergey.senozhatsky@gmail.com, linux-kernel@vger.kernel.org,
	tsoni@codeaurora.org
Subject: Re: sched_clock and device suspend/resume
Date: Wed, 10 Jul 2019 21:15:49 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.1907102114480.1758@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190710151334.49158be3@gandalf.local.home>

On Wed, 10 Jul 2019, Steven Rostedt wrote:
> 
> [ Removed the two emails that were bouncing ]
> 
> On Wed, 10 Jul 2019 21:06:57 +0200 (CEST)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> > > > > sched_clock_continuous() ? (I know, horrible name), that simply keeps
> > > > > track of the time delta at suspend and returns:
> > > > > 
> > > > > 	sched_clock() + delta;    
> > > > 
> > > > Which you get already when you do
> > > > 
> > > > # echo boot > /sys/kernel/debug/tracing/trace_clock
> > > >   
> > > 
> > > So basically the answer here is to change printk to use
> > > ktime_get_boot_fast_ns() instead of local_clock()?  
> > 
> > Aargh. That was tracing.
> > 
> > There was a patchset floating around which actually implemented that clock
> > choice for sched_clock as well. Don't know why that was never merged.
> 
> Will it cause issues with the scheduler though. If it doesn't stop
> during suspend, can't that make the scheduler think that processes were
> using the CPU during the entire suspend and screw up the accounting?

Duh. My brain is not working.

Not sched_clock, the patches were for printk so you could select a printk
clock. Can't find them right now.

Thanks,

	tglx

  reply	other threads:[~2019-07-10 19:16 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1d6ef4687c87dd4d2ec88d0d593a9c1d@codeaurora.org>
2019-07-10 15:36 ` sched_clock and device suspend/resume Steven Rostedt
2019-07-10 18:35   ` Thomas Gleixner
2019-07-10 18:57     ` Steven Rostedt
2019-07-10 19:06       ` Thomas Gleixner
2019-07-10 19:13         ` Steven Rostedt
2019-07-10 19:15           ` Thomas Gleixner [this message]
2019-07-10 19:22             ` Thomas Gleixner

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:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

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

  git send-email \
    --in-reply-to=alpine.DEB.2.21.1907102114480.1758@nanos.tec.linutronix.de \
    --to=tglx@linutronix.de \
    --cc=chang-an.chen@mediatek.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=john.stultz@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=pmladek@suse.com \
    --cc=psodagud@codeaurora.org \
    --cc=rostedt@goodmis.org \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tsoni@codeaurora.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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).