Re: [patch, v2.6.22-rc6] sys_time() speedup

* Mark Lord <[email protected]> wrote:

> Ingo Molnar wrote:
> >Subject: [patch] sys_time() speedup
> >From: Ingo Molnar <[email protected]>
> >
> >improve performance of sys_time(). sys_time() returns time in seconds, 
> >but it does so by calling do_gettimeofday() and then returning the 
> >tv_sec portion of the GTOD time. But the data structure "xtime", which 
> >is updated by every timer/scheduler tick, already offers HZ granularity 
> >time.
> 
> How well synchronized is xtime with real-time ?

it's updated by every jiffy.

> Programs invoking sys_time() do expect it to be as accurate as 
> gettimeofday(), even if only at 1-second boundaries.

yes.

	Ingo
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