Re: [RFC,PATCH 0/2] do_wait() wakeup optimization

From: Oleg Nesterov
Date: Tue Jun 23 2009 - 13:46:22 EST

On 06/23, Ratan Nalumasu wrote:
> Yes, it is something we really need. The specific case I have (hundreds of
> NTPL threads in a program, and each thread managing a child process), the
> CPU load is >99% with NTPL threads, near 0% with the patch

Thanks. Did you test this patch, or do you mean the previous one?

> So, yes, the complication is worthwhile.

I am asking because I am not sure this change is enough, note the
"We can make child_wait_callback() more clever later" in the changelog.

__wake_up_parent() passes key = p, but we can pass more info and do
additional checks in child_wait_callback().


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