Re: new OOM heuristic failure (was: Re: VM: qsbench)

Lorenzo Allegrucci
2001-11-02T17:34:58Z

At 14.00 02/11/01 +0100, Stephan von Krawczynski wrote:
>Hello Lorenzo,
>
>please find attached next vmscan.c patch which sums up the delayed swap_out
>(first patch), the fix for not swapping when nr_pages is reached, and (new) the
>idea to swap more pages in one call to swap_out if priority gets higher.
>
>I have not the slightest idea what all this does to the performance. Especially
>the "more" swap_out code is a pure try-and-error type of thing. Can you do some
>testing please?

vmscan-patch2 looks slightly slower than vmscan-patch:

lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
70.800u 2.210s 2:27.96 49.3% 0+0k 0+0io 18551pf+0w
lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
70.600u 2.150s 2:28.49 48.9% 0+0k 0+0io 18728pf+0w
lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
70.690u 2.080s 2:28.77 48.9% 0+0k 0+0io 18753pf+0w
1:03 kswapd

Same test with 400M of swap:

lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
72.180u 2.110s 2:31.37 49.0% 0+0k 0+0io 18696pf+0w
lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
70.400u 2.200s 2:31.04 48.0% 0+0k 0+0io 18940pf+0w
lenstra:~/src/qsort> time ./qsbench -n 90000000 -p 1 -s 140175100
70.950u 2.210s 2:32.35 48.0% 0+0k 0+0io 19115pf+0w
1:02 kswapd

kswapd still takes many cycles.

--
Lorenzo