Call for testers, amd64 only, new scheduler.
Jeff Roberson
jroberson at chesapeake.net
Wed Jun 13 02:29:17 UTC 2007
This is actually a ULE derivative that I have been discussing for some
time. It is now stable enough that I would like more people to bang on it
and give feedback about performance and tell me about any stability
problems they encounter.
You can see in the following graph that the ramp-up times for the sysbench
benchmark have improved although the tail has suffered a little:
http://people.freebsd.org/~jeff/sysbench.png
The new scheduler is FreeBSD-7.0-ULE-pcpulocks. On my dual cpu system the
results are much less ambiguous. It's a 10-15% win on sysbench across the
board. This also improves an artificial thread benchmark included with
sysbench by 500% on an 8 way and gives us ebizzy numbers on par with or
better than linux.
It also includes a mechanism that should improve bde's nfs buildworld
times, although I have not yet verified that. Hopefully he'll try it as
well. It should reduce CPU idle time while also negating the effects of
thrashing other cpus run queues in the idle thread.
The new patch is at: http://people.freebsd.org/~jeff/schedsmp.diff
You have to change your scheduler to SCHED_SMP. x86 support is
forthcoming. Depending on feedback and what re thinks I am going to
consider replacing ULE entirely with SCHED_SMP or committing this as a
seperate scheduler for 7.0.
Thanks,
Jeff
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