Messages in this thread | | | Date | Sat, 21 Sep 2002 14:56:26 +0200 | From | Andries Brouwer <> | Subject | quadratic behaviour |
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On Thu, Sep 19, 2002 at 03:11:57PM +0200, Andries Brouwer wrote: > On Thu, Sep 19, 2002 at 05:05:17AM +0200, Ingo Molnar wrote:
> > because, as mentioned before, that particular loop i fixed in 2.5.35. > > But now that I look at patch-2.5.35 > I don't see any improvement: for_each_task() is now called > for_each_process(), but otherwise base.c is just as quadratic > as it was. > > So, why do you think this problem has been fixed?
Let me repeat this, and call it an observation instead of a question, so that you do not think I am in doubt.
If you have 20000 processes, and do ps, then get_pid_list() will be called 1000 times, and the for_each_process() loop will examine 10000000 processes.
Unlike the get_pid() situation, which was actually amortized linear with a very small coefficient, here we have a bad quadratic behaviour, still in 2.5.37.
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