lkml.org 
[lkml]   [2016]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/5] sched,time: Count actually elapsed irq & softirq time
From
Date
On Tue, 2016-08-09 at 11:59 +0800, Wanpeng Li wrote:
> Hi Rik,
> 2016-07-13 22:50 GMT+08:00 Frederic Weisbecker <fweisbec@gmail.com>:
> > From: Rik van Riel <riel@redhat.com>
> >
> > Currently, if there was any irq or softirq time during 'ticks'
> > jiffies, the entire period will be accounted as irq or softirq
> > time.
> >
> > This is inaccurate if only a subset of the time was actually spent
> > handling irqs, and could conceivably mis-count all of the ticks
> > during
> > a period as irq time, when there was some irq and some softirq
> > time.
> >
> > This can actually happen when irqtime_account_process_tick is
> > called
> > from account_idle_ticks, which can pass a larger number of ticks
> > down
> > all at once.
> >
> > Fix this by changing irqtime_account_hi_update,
> > irqtime_account_si_update,
> > and steal_account_process_ticks to work with cputime_t time units,
> > and
> > return the amount of time spent in each mode.
>
> Do we need to minus st cputime from idle cputime in
> account_idle_ticks() when noirqtime is true? I try to add this logic
> w/ noirqtime and idle=poll boot parameter for a full dynticks guest,
> however, there is no difference, where I miss?

Yes, you are right. The code in account_idle_ticks()
could use the same treatment.

I am not sure why it would not work, though...

--

All Rights Reversed.[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2016-08-09 16:41    [W:0.156 / U:1.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site