Turn off hyperthreading on dual core Atom?
brett at lariat.net
Mon Aug 29 21:15:13 UTC 2011
At 01:55 PM 8/29/2011, Bruce Cran wrote:
>Actually, the ULE scheduler does know about HyperThreading and the
>topology of such CPUs. I don't know what it does with the
>information, but it probably works to optimize cache usage etc.
Alas, during a recent kernel build, I used the -j2 command line
option in "make" and watched as the scheduler repeatedly assigned
two instances of cc (the most CPU-intensive program) to the same core.
During that process, I also watched CPU utilization in top(1). The
peak was 46% idle, which means that HTT appeared to be making at
most a 4% difference. (If the peak were 50% idle, HTT would be
doing nothing at all, because top(1) can't tell that there aren't
really 4 CPUs.)
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