Possible documentation issue?

[Josh Ulrich]

Hello,

The paragraph below states the default scheduler doesn't optimize for
HTT but the default scheduler in the GENERIC kernel in 7.1 is now
SCHED_ULE, which includes "CPU topology awareness, including for
hyper-threading." (sched_ule(4))  I thought SCHED_ULE differentiates
between physical and logical processors.  Is that incorrect?

From: http://www.freebsd.org/releases/7.1R/hardware.html
"FreeBSD will take advantage of HyperThreading (HTT) support on Intel
CPUs that support this feature. A kernel with the options SMP feature
enabled will automatically detect the additional logical processors.
The default FreeBSD scheduler treats the logical processors the same
as additional physical processors; in other words, no attempt is made
to optimize scheduling decisions given the shared resources between
logical processors within the same CPU. Because this naive scheduling
can result in suboptimal performance, under certain circumstances it
may be useful to disable the logical processors with the the
machdep.hlt_logical_cpus sysctl variable. It is also possible to halt
any CPU in the idle loop with the machdep.hlt_cpus sysctl variable.
The smp(4) manual page has more details."

Best Regards,
Josh
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