advantage using multiple cpus

[phobos at rootme.org]

On Mon, May 07, 2007 at 07:20:18PM +0200, olaf.selke at blutmagie.de wrote 0.8K bytes in 18 lines about:
: I'm running tor on a dual Xeon Linux box having the numcpus param set to
: the value of four. Bios reports two Xeon cpus with hyperthreading to the
: Linux kernel 2.6.18 as four processors. Nevertheless throughput appears
: to be limited by the cpu running the main thread doing nearly all the work:

	You want the NumCPU to be set to 2.  You have two physical cpus.
	The way the linux kernel interprets the HT part looks like 2
	more cpus, but in reality, the kernel scheduler knows you only have 2, not 4.

	I suggest setting it to 2 and seeing if performance improves for
	you.  Hopefully, empirical research on a sample size of one
	system avoids a lengthy thread about HT vs. real cpus.

-- 
Andrew