Messages in this thread | | | Date | Thu, 12 Aug 2004 10:08:22 +0200 | From | "Prakash K. Cheemplavam" <> | Subject | Re: Scheduler fairness problem on 2.6 series |
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Con Kolivas wrote: | Prakash K. Cheemplavam wrote: | |> 124910 9.8170 vmlinux tcp_poll |> 123356 9.6949 vmlinux sys_select |> 85634 6.7302 vmlinux do_select |> 71858 5.6475 vmlinux sysenter_past_esp |> 62093 4.8801 vmlinux kfree |> 51658 4.0600 vmlinux __copy_to_user_ll |> 37495 2.9468 vmlinux max_select_fd |> 36949 2.9039 vmlinux __kmalloc |> 22700 1.7841 vmlinux __copy_from_user_ll |> 14587 1.1464 vmlinux do_gettimeofday |> | It looks like your select timeouts are too short and when the cpu load | goes up they repeatedly timeout wasting cpu cycles. | I quote from `man select_tut` under the section SELECT LAW: | | 1. You should always try use select without a timeout. Your program | should have nothing to do if there is no data available. Code | that depends on timeouts is not usually portable and difficult | to debug. |
Thanks for your explanation. I cannot do anything about it, as it is mpich related. So I'll ask them if they could change its behaviour a bit so that it eats less CPU on a single CPU machine.
Cheers,
Prakash -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org
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