Messages in this thread | | | Date | Sun, 21 Apr 2002 18:00:22 +0000 | From | Pavel Machek <> | Subject | Re: Why HZ on i386 is 100 ? |
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Hi!
> Davide> i still have pieces of paper on my desk about tests done on > Davide> my dual piii where by hacking HZ to 1000 the kernel build > Davide> time went from an average of 2min:30sec to an average > Davide> 2min:43sec. that is pretty close to 10% > > The last time I measured timer tick overhead on ia64 it was well below > 1% of overhead. I don't really like using kernel builds as a > benchmark, because there are far too many variables for the results to > have any long-term or cross-platform value. But since it's popular, I > did measure it quickly on a relatively slow (old) Itanium box: with > 100Hz, the kernel compile was about 0.6% faster than with 1024Hz > (2.4.18 UP kernel).
.5% still looks like a lot to me. Good compiler optimization is .5% on average...
And think what it does with old 386sx.. Maybe time for those "tick on demand" patches? Pavel -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.
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