From: Divyesh Shah on
On Sat, Jun 12, 2010 at 12:18 AM, Ingo Molnar <mingo(a)elte.hu> wrote:
>
> * Divyesh Shah <dpshah(a)google.com> wrote:
>
>> This will take care of the pre-emptive kernel issue and the unbounded
>> TSC drift problem. We will lose resolution though in some cases.
>
>> - � � blkg->stats.start_group_wait_time = sched_clock();
>> + � � blkg->stats.start_group_wait_time = ktime_to_ns(ktime_get());
>
> Ugh!
>
> ktime_get() can have insanely high overhead. Peter has added local_clock(), if
> then you should use that and apply checks to make sure the result isnt
> negative.

Ok. The negative checks are already in the code.

>
> � � � �Ingo
>
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