Re: [ADMIN] v7.1b4 bad performance

[Bruce Momjian]

> TL> I vote for commit_delay = 0, unless someone can show cases where
> TL> positive delay is significantly better than zero delay.
> 
> BTW, for modern versions of FreeBSD kernels, there is HZ kernel option
> which describes maximum timeslice granularity (actually, HZ value is
> number of timeslice periods per second, with default of 100 = 10 ms). On
> modern CPUs HZ may be increased to at least 1000, and sometimes even to
> 5000 (unfortunately, I haven't test platform by hand).
> 
> So, maybe you can test select granularity at ./configure phase and then
> define default commit_delay accordingly.

According to the BSD4.4 book by Karels/McKusick, even though computers
are faster now, increasing the Hz doesn't seem to improve performance. 
This is probably because of cache misses from context switches.

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