Messages in this thread | | | Date | Mon, 7 Sep 2009 16:14:37 +0800 | From | "lookeylam" <> | Subject | About CPU's Load Balance and CFS functions |
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Hello: I am not sure this is the right maillist to ask this question. I just have a try. I have a test on Dell 1950 with 8 cpus on board for testing the apache by ab command. And I find that in linux 2.6.18. The processes forked by apache are not well distributed on these 8 cpus. linux 2.6.23 is a little better than 2.6.18, but still some cpus are running busy and some cpus remains idle. While in 2.6.30, these 8 cpus are well used and the percentage of each cpu is nearly the same. And when I start the control group with cpuset type with sched_relax_domain_level( with value 3,4,5). The result of ab is 50ms better than test results without control group.
I attribute this situation to to load_balance but not CFS, because CFS is just a scheduler for orgnizing the process inside one cpu, while load_balance is the main character to control the process and load between different cpus. But when i give out this conclusion, I confuse about the differences of these three kernels of load_balance.
My questions are the above conclusion is right or not? How would these situation happen and why? I read the code of the kernel but I am still not sure.
Thanks.
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