Subject: arm64 sched_clock cpu accounting

From: [email-masked] (Christoffer Dall)
Date: Wed, 2 Dec 2015 19:07:41 +0100

Hi Mario,

On Wed, Nov 18, 2015 at 06:20:03PM -0800, Mario Smarduch wrote:
> Also with tick accounting enabled, and periodic timer HZ set to 1000 no irq time
> is reported. That's with running a ping flood - 1200 int/s, not sure why
> wouldn't any irq time be reported? The other two modes report irq time as expected.
> 
> On 11/18/2015 11:46 AM, Mario Smarduch wrote:
> > Hello,
> >   I noticed sched clock accounting can be enabled when arch-timer is
> > initialized. But arm64 doesn't appear to have 'HAVE_IRQ_TIME_ACCOUNTING'
> > selected (as of mainline 4.4-rc1) and IRQ_TIME_ACCOUNTING can't be selected.
> > After adding it to arch/arm64/Kconfig, option appears to work fine. Depending on
> > need all accounting options are fine, but irq time accounting appears to be most
> > preferable.
> > 
> > Any thoughts? Is it fine to enable it?
> > 
Is any of this related to KVM?

-Christoffer