Re: PM regression in next
- Date: Thu, 11 Jan 2018 17:20:19 -0800
- From: Tony Lindgren <tony@xxxxxxxxxxx>
- Subject: Re: PM regression in next
* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [180112 00:45]:
> On Thu, 11 Jan 2018 16:23:22 -0800 Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> > * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [180112 00:18]:
> > > On Thu, 11 Jan 2018 16:01:13 -0800 Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> > >
> > > > Hi all,
> > > >
> > > > I'm seeing a considerable idle power consumption regression in
> > > > Linux next, with power consumption for my idle test system going
> > > > to 17.5mW compared to the usual 8mW on my test device.
> > > >
> > > > Git bisect points to merge commit e130bc1d00a4 ("Merge branch
> > > > 'akpm-current/current'") being the first bad commit.
> > > >
> > > > I have also verified that commit 70286688e5ad ("ipc/mqueue.c:
> > > > have RT tasks queue in by priority in wq_add()") is good, and
> > > > commit e2d7fe89e8ae ("Merge remote-tracking branch
> > > > 'init_task/init_task'") is good.
> > >
> > > Do you mean that everything up to and including 70286688e5ad
> > > ("ipc/mqueue.c: have RT tasks queue in by priority in wq_add()") is
> > > good?
> > Yes I'm not seeing the regression in your branch at commit
> > 70286688e5ad. I'm seeing it only with the merge commit
> > e130bc1d00a4.
> That's weird. All I'm seeing between 70286688e5ad and end-of-mm is:
Well there are some changes in merge commit e130bc1d00a4..
> And I don't see how any of those can cause this. Did anything else
> change, like context switch rates, interrupt rates, etc?
Well I tried to measure suspend power consumption and noticed
that system suspend fails too hand hangs the network device:
# echo mem > /sys/power/state
[ 32.577850] PM: suspend entry (deep)
[ 32.582031] PM: Syncing filesystems ... done.
[ 32.598083] Freezing user space processes ... (elapsed 0.002 seconds) done.
[ 32.608398] OOM killer disabled.
[ 32.611846] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
[ 32.622192] Suspending console(s) (use no_console_suspend to debug)
[ 32.651123] dpm_run_callback(): mdio_bus_suspend+0x0/0x24 returns 4352
[ 32.651428] PM: Device 2c000000.ethernet-ffffffff:01 failed to suspend: error 4352
[ 32.653289] PM: Some devices failed to suspend, or early wake event detected
[ 32.685455] OOM killer enabled.
[ 32.688629] Restarting tasks ... done.
[ 32.695983] PM: suspend exit
ash: write error: Bad address
That too works just fine at commit 70286688e5ad.