Re: [PATCH 1/2] Add scaled time to taskstats based process accounting

From: Balbir Singh
Date: Fri Aug 17 2007 - 00:48:58 EST


Michael Neuling wrote:
>> I'd also request for you to add a cpu_scaled_run_real_total for use
>> by delay accounting. cpu_scaled_run_real_total should be similar in
>> functionality to cpu_run_real_total.
>
> Will do. Should I add cpu_scaled_run_real_total to the end of the
> struct taskstat, or next to cpu_run_real_total?
>

Please add it to the end, that helps maintain binary compatibility
across all versions of taskstats.

>>> /* Note: this timer irq context must be accounted for as well. */
>>> - if (user_tick)
>>> + if (user_tick) {
>>> account_user_time(p, jiffies_to_cputime(1));
>>> - else
>>> + account_user_time_scaled(p, jiffies_to_cputime(1));
>>> + } else {
>>> account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1));
>>> + account_system_time_scaled(p, jiffies_to_cputime(1));
>>> + }
>> I am a little confused here, scaled accounting and regular accounting
>> go hand in hand?
>
> We need to account for scaled and normal time in this generic code.
> All other calls to account_(user|system)_time are in arch code.
>

So the assumption here is that we ran at full frequency during
this time, is my understanding correct?

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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