Re: slow down in 2.6 vs 2.4

[Peter Williams]

Con Kolivas wrote:
> Hi Phy
>
> You said:
> Over the last two days I have been struggling with
> understanding why 2.6.x kernel is slower than
> 2.4.21/23 kernels.  I think I have a test case which
> demostrates this issue.
> make times:
>
> 2.4.21:
> 323.68user 56.07system 6:35.77elapsed 95%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (3138783major+3818347minor)pagefaults
> 0swaps
>
> 2.6.7-rc3-s63 (SPA scheduler):
> 334.01user 69.86system 7:01.47elapsed 95%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (13301major+6931745minor)pagefaults
> 0swaps
>
> 2.6.7-rc3:
> 336.17user 68.41system 7:02.47elapsed 95%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (13301major+6931745minor)pagefaults
> 0swaps
>
>
> ----
> Your 2.4 compile is showing a massive number of major page faults.

Seems to be roughly the same total number of page faults in all three 
cases but there's been a big shift from majors to minors for the 2.6 
kernels which I would have thought would improve performance?

Peter
--
Dr Peter Williams                                pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
 -- Ambrose Bierce

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