* Michael Gerdau <[EMAIL PROTECTED]> wrote:
> > Here i'm assuming that the vmstats are directly comparable: that
> > your number-crunchers behave the same during the full runtime - is
> > that correct?
>
> Yes, basically it does (disregarding small fluctuations)
ok, good.
> I'll see whether I can produce some type of absolute performance
> measure as well. Thinking about it I guess this should be fairly
> simple to implement.
oh, you are writing the number-cruncher? In general the 'best'
performance metrics for scheduler validation are the ones where you have
immediate feedback: i.e. some ops/sec (or ops per minute) value in some
readily accessible place, or some "milliseconds-per-100,000 ops" type of
metric - whichever lends itself better to the workload at hand. If you
measure time then the best is to use long long and nanoseconds and the
monotonic clocksource:
unsigned long long rdclock(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
}
(link to librt via -lrt to pick up clock_gettime())
The cost of a clock_gettime() (or of a gettimeofday()) can be a couple
of microseconds on some systems, so it shouldnt be done too frequently.
Plus an absolute metric of "the whole workload took X.Y seconds" is
useful too.
Ingo
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