ULE/SCHED_SMP diff for 7.0
Dmitry Morozovsky
marck at rinet.ru
Thu Jul 19 08:16:43 UTC 2007
On Wed, 18 Jul 2007, Jeff Roberson wrote:
JR> > Works for me with MSI S420 lapton (core2duo T2400) on fresh -CURRENT/i386
JR> > CPU: Genuine Intel(R) CPU T2400 @ 1.83GHz (1833.41-MHz
JR> > 686-class CPU)
JR> >
JR> > However, make -j3 buildworld buildkernel (trimmed GENERIC) time degraded
JR> > by 7%:
JR> >
JR> > +------------------------------------------------------------------------------+
JR> > N Min Max Median Avg Stddev
JR> > x 5 36.33 36.77 36.45 36.486
JR> > + 5 38.87 39.23 39.03 39.042
JR> > Difference at 95.0% confidence
JR> > 2.556 +/- 0.216322
JR> > 7.00543% +/- 0.59289%
JR> > (Student's t, pooled s = 0.148324)
JR> >
JR> > before = kernel with SCHED_4BSD, after = SCHED_ULE with your patchset.
JR> > Both
JR> > are without WITNESS/INVARIANTS.
JR>
JR> Hi Dmitry,
JR>
JR> Can you test with http://people.freebsd.org/~jeff/sched_ule.c? I believe
JR> this will somewhat improve the situation with buildkernel. I have tested
JR> with my own core2duo laptop. The first run after reboot is now about 7%
JR> faster than before. Subsequent runs are not improved as much. Only 2-3%.
JR> You can also try tuning sysctl kern.sched.steal_thresh down as low as 1 to
JR> see how much this may help. Unfortunately lower values tend to really hurt
JR> other tests.
Well, I'm a bit puzzled: with new sched_ule.c system+user time slightly
decreases (within one minute), while real time goes up from 39 to 44 minutes!
And most of the time I see 10-50% of idle in top.
Any hints?
Sincerely,
D.Marck [DM5020, MCK-RIPE, DM3-RIPN]
------------------------------------------------------------------------
*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
------------------------------------------------------------------------
More information about the freebsd-current
mailing list