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.

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