Re: Useful fork info? WAS Re: [BENCHMARK] fork_load module tested

Ingo Molnar (mingo@elte.hu)
Thu, 26 Sep 2002 10:25:47 +0200 (CEST)


On Thu, 26 Sep 2002, Con Kolivas wrote:

> fork_load:
> Kernel Time CPU Ratio
> 2.4.19 97.11 67% 1.33
> 2.4.19-ck7 72.34 92% 0.99
> 2.5.38 75.32 92% 1.03
> 2.5.38-mm2 74.99 92% 1.03
>
> 2.4.19: Children forked: 32750
> 2.4.19-ck7: Children forked: 6477
> 2.5.38: Children forked: 5545
> 2.5.38-mm2: Children forked: 5351
>
> You can see clearly repeatedly forking a new process significantly slows
> down compile time for 2.4.19 but not the O(1) based kernels. However,
> the number of processes that are forked is significantly reduced.

shouldnt the CPU load be 100% for such a test? If it isnt then perhaps
some other thing factors in. VM load? And i dont understand how a faster
kernel forks less children in the end. Perhaps the test is hitting some
sort of resource limit which has a different default in 2.5?

Ingo

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