Re: VM Report was:Re: Break 2.4 VM in five easy steps

Mike Galbraith
2001-06-08T12:51:54Z

On Fri, 8 Jun 2001, Jonathan Morton wrote:

> http://www.chromatix.uklinux.net/linux-patches/vm-update-2.patch
>
> Try this. I can't guarantee it's SMP-safe yet (I'm leaving the gurus to
> that, but they haven't told me about any errors in the past hour so I'm
> assuming they aren't going to find anything glaringly wrong...), but you
> might like to see if your performance improves with it. It also fixes the
> OOM-killer bug, which you refer to above.
>
> Some measurements, from my own box (1GHz Athlon, 256Mb RAM):
>
> For the following benchmarks, physical memory availability was reduced
> according to the parameter in the left column. The benchmark is the
> wall-clock time taken to compile MySQL.
>
> mem= 2.4.5 earlier tweaks now
> 48M 8m30s 6m30s 5m58s
> 32M unknown 2h15m 12m34s
>
> The following was performed with all 256Mb RAM available. This is
> compilation of MySQL using make -j 15.
>
> kernel: 2.4.5 now
> time: 6m30s 6m15s
> peak swap: 190M 70M
>
> For the following test, the 256Mb swap partition on my IDE drive was
> disabled and replaced with a 1Gb swapfile on my Ultra160 SCSI drive. This
> is compilation of MySQL using make -j 20.
>
> kernel: 2.4.5 now
> time: 7m20s 6m30s
> peak swap: 370M 254M
>
> Draw your own conclusions. :)

(ok;)

Hi,

I gave this a shot at my favorite vm beater test (make -j30 bzImage)
while testing some other stuff today.

seven identical runs, six slightly different kernels plus yours.

real 11m23.522s 2.4.5.vm-update-2
user 7m59.170s
sys 0m37.030s
user : 0:08:07.06 65.6% page in : 642402
nice : 0:00:00.00 0.0% page out: 676820
system: 0:02:09.44 17.4% swap in : 105965
idle : 0:02:05.66 16.9% swap out: 162603

real 10m9.512s 2.4.5.virgin
user 7m55.520s
sys 0m35.460s
user : 0:08:02.66 72.2% page in : 535186
nice : 0:00:00.00 0.0% page out: 377992
system: 0:01:37.78 14.6% swap in : 99445
idle : 0:01:28.14 13.2% swap out: 81926

real 10m48.939s 2.4.5.virgin+reclaim.marcelo
user 7m54.960s
sys 0m36.240s
user : 0:08:02.33 68.0% page in : 566239
nice : 0:00:00.00 0.0% page out: 431874
system: 0:01:56.02 16.4% swap in : 108633
idle : 0:01:50.61 15.6% swap out: 96415

real 9m54.466s 2.4.5.virgin+reclaim.mike (icky 'bleeder valve')
user 7m57.370s
sys 0m35.890s
user : 0:08:04.74 74.1% page in : 527678
nice : 0:00:00.00 0.0% page out: 405259
system: 0:01:12.01 11.0% swap in : 98616
idle : 0:01:37.47 14.9% swap out: 91492

real 9m12.198s 2.4.5.tweak
user 7m41.290s
sys 0m34.840s
user : 0:07:47.69 76.8% page in : 452632
nice : 0:00:00.00 0.0% page out: 399847
system: 0:01:17.08 12.7% swap in : 75338
idle : 0:01:03.97 10.5% swap out: 88291

real 9m41.563s 2.4.5.tweak+reclaim.marcelo
user 7m59.880s
sys 0m34.690s
user : 0:08:07.22 73.4% page in : 515433
nice : 0:00:00.00 0.0% page out: 545762
system: 0:01:35.34 14.4% swap in : 88425
idle : 0:01:21.11 12.2% swap out: 125967

real 9m47.682s 2.4.5.tweak+reclaim.mike
user 8m2.190s
sys 0m34.550s
user : 0:08:09.57 75.7% page in : 513166
nice : 0:00:00.00 0.0% page out: 473539
system: 0:01:20.27 12.4% swap in : 83127
idle : 0:01:16.89 11.9% swap out: 108886

Conclusion:

Your patch hits the cache too hard and pays through the nose for
doing so.. at least under this hefty weight load it does.