Re: ULE/SCHED_SMP diff for 7.0, buildkernel & thanks.

2007/7/17, Abdullah Ibn Hamad Al-Marri <almarrie_at_gmail.com>:
> On 7/17/07, Jeff Roberson <jroberson_at_chesapeake.net> wrote:
> > With regards to buildkernel times;  I do not want to sacrafice performance
> > on other benchmarks to improve buildkernel.  The problem is that 4BSD is
> > as agressive as possible at scheduling work on idle cores.  This behavior
> > that helps one buildworld hurts on other, in my opinion, more important
> > benchmarks.
> >
> > For example: http://people.freebsd.org/~jeff/sysbench.png
> >
> > ULE is 33% faster than SCHED_4BSD at this mysql test.  This is a direct
> > result of prefering to idle to make more efficient scheduling decisions.
> > ULE is also faster at various networking benchmarks for similar reasons.
> >
> > I also believe that while the real time may be slower on buildworld the
> > system and user time will be smaller by a degree greater than the delta in
> > real time.  This means that while you're building packages you have a
> > little more cpu time leftover to handle other tasks.  Furthermore, as the
> > number of cores goes up things start to tip in favor of ULE although this
> > is somewhat because it's harder for even 4BSD to keep them busy due to
> > disk bandwidth.
> >
> > Thanks everyone for testing.  Can someone confirm that they have tested
> > with x86 rather than amd64?  I will probably commit later today.
> >
> > Thanks,
> > Jeff
>
> Did you compare it to latest Linux fixes? is FreeBSD + ULE + MySQL
> still faster than linux?

Just look at the link Jeff posted, it seems very well explaining :).

Attilio


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