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performance differences: "maxcpus=1" vs. "echo 0 > /sys/devices/system/cpu/cpu1/online"

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To: <linux-kernel@...>
Date: Tuesday, March 25, 2008 - 9:47 am

Hi, 

what is the difference between booting a dual core
machine with "maxcpus=1" or by deactivating the second
core at run time with "echo 0 >
/sys/devices/system/cpu/cpu1/online"?

I observed a funny behaviour of apache ant: although
it uses javac which is single threaded, a compile run
with "maxcpus=1" is actually faster than a compile run
with both cores activated. But with the second core
deactivated using "echo 0 >
/sys/devices/system/cpu/cpu1/online" it is even slower
than with both cores.

Is here any method to get the exact same behaviour of
"maxcpus=1" with disabling the second core only
temporarily? So that the second core could be disabled
before the ant execution and enabled after the ant
execution?

Thanks a lot!


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Messages in current thread:
performance differences: "maxcpus=1" vs. "echo 0 > /sys/d..., Michael Meyer, (Tue Mar 25, 9:47 am)
Re: performance differences: "maxcpus=1" vs. "echo 0 &gt; /s..., Wander Winkelhorst, (Tue Mar 25, 1:49 pm)
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