Kernel forces machdep.hlt_cpus, how to change?
freebsd at walter.transip.nl
Thu Jan 5 09:34:08 PST 2006
I'm testing out FreeBSD 6.0R on a Dual Xeon. I want to do some
benchmarking of hyperthreading before I put this machine into use, so
I am trying to turn off the HLTing of logical cpu's.
A stock "SMP" kernel without any options gives the following sysctl's
on this machine:
So even though I have hlt_logical_cpus at 0, the kernel seems to have
decided to HLT my cpu's 8 and 2, the 'logical' threads on each Xeon I
I've tried to get around this by setting the following:
test# cat /boot/loader.conf
But still after booting I get the same result with the cpu's HLTed.
I'm not sure if using them for user processes actually helps, but I'd
like to experiment with the setting. Any ideas how I should accomplish
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