linux-kernel - Re: Regression in v5.0-rc1 with autosuspend hrtimers

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Message-ID: <20190110075444.GA26920@lenoch>
Date:   Thu, 10 Jan 2019 08:54:44 +0100
From:   Ladislav Michl <ladis@...ux-mips.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "open list:THERMAL" <linux-pm@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        Linux OMAP Mailing List <linux-omap@...r.kernel.org>
Subject: Re: Regression in v5.0-rc1 with autosuspend hrtimers

On Thu, Jan 10, 2019 at 08:50:14AM +0100, Vincent Guittot wrote:
> On Thu, 10 Jan 2019 at 08:46, Ladislav Michl <ladis@...ux-mips.org> wrote:
> >
> > On Wed, Jan 09, 2019 at 11:06:34PM +0100, Rafael J. Wysocki wrote:
> > > On Wed, Jan 9, 2019 at 7:05 PM Vincent Guittot
> > > <vincent.guittot@...aro.org> wrote:
> > > >
> > > > On Wed, 9 Jan 2019 at 18:26, Ladislav Michl <ladis@...ux-mips.org> wrote:
> > > > >
> > > > > On Wed, Jan 09, 2019 at 05:32:31PM +0100, Vincent Guittot wrote:
> > > > > > On Wed, 9 Jan 2019 at 17:07, Ladislav Michl <ladis@...ux-mips.org> wrote:
> > > > > > >
> > > > > > > On Wed, Jan 09, 2019 at 03:12:25PM +0100, Vincent Guittot wrote:
> > > > > > > > Please keep all thread list when replying :-)
> > > > > > >
> > > > > > > Ahh, sorry for that...
> > > > > > > [snip]
> > > > > > > > On Wed, 9 Jan 2019 at 14:33, Ladislav Michl <ladis@...ux-mips.org> wrote:
> > > > > > > > > I agree, but it doea all the magic correctly, so you won't need
> > > > > > > > > to touch that code is ktime_t changes (I know, unlikely..)
> > > > > > > >
> > > > > > > > But the current implementation doesn't care of any changes in ktime_t
> > > > > > > > as it uses raw ns
> > > > > > >
> > > > > > > Fair enough, so let's go back to:
> > > > > >
> > > > > > This one looks good for me
> > > > >
> > > > > Lets split is for 'comments fix' patch, which was just send and 'the rest'.
> > > > > Now, 'the rest' can either be v2 of your "PM/runtime: Fix autosuspend_delay on
> > > > > 32bits arch" or will wait for 5.1. You decide :)
> > > >
> > > > I don't really mind.
> > > >
> > > > Rafael,
> > > > Do you prefer to only take the fix for u64 casting problem or do you
> > > > prefer to also take the optimization below in one single patch ?
> > >
> > > The casting problem is a bug and the optimization is next release
> > > material in my view.  Please send the optimization separately.
> >
> > Ok, will send that separately in a few moments...
> > Btw, u64 casting problem seems to be still present in rpm_suspend while
> > computing slack for autosuspend delay greater than 25% of 2^31 (2^33) ns.
> 
> Good point. I will add it to the fix as well

Another nit then, for (u64)(autosuspend_delay) is (u64)autosuspend_delay
enough :)

I'll wait for your v2 before sending optimization patch.

> > Not sure if that triggers any real bug.