VM: 2.4.10ac4 vs. 2.4.11pre2

chris
2001-10-06T12:20:16Z

Hi,

Here are some test results. Results are averaged over multiple runs.
Comments and conclusions below.

2.4.11pre2 2.4.10ac4
dbench 8 34Mbyte/sec 40Mbyte/sec
dbench 32 7.7Mbyte/sec 14Mbyte/sec
bonnie++ write 17.5Mbyte/sec 18Mbyte/sec
bonnie++ rewrite 5.6Mbyte/sec 5.8Mbyte/sec
bonnie++ read 24Mbyte/sec 24.5Mbyte/sec
kernel stress build 212min24s 229m54s
linear swap test 1m30s 2m15s
bonnie++ creat() 7200 9600 [*]
bonnie++ stat() 2100 9000 [*]
bonnie++ unlink() 5300 30000 [*]

[*] either the ext2 directory optimization in 2.4.10ac is influencing the
test, or 2.4.11pre2 VM has a problem caching inodes.

Comments + conclusions
----------------------

- The 2.4.11pre2 VM is considerably more stable, where "stable" is defined
as repeatable test scores and consistent performance. The 2.4.10ac4 VM is
all over the place.

- Both kernels exhibit similar interactive response under load.

- The 2.4.11pre2 VM performs substantially better in tests which invoke
swapping.

- Surprisingly, the 2.4.10ac4 kernel does much much better at dbench. The
2.4.11pre2 performance is alleged to have regressed since 2.4.10pre10?

- I have not tried 2.4.11pre4, but the report of streaming i/o causing
swapping is concerning.

Note that the above results were generated using a very simple (and
extensible) script. VM developers would do well to spend the 30 seconds
writing a similar script, and post results along with proposed VM patches.

Cheers
Chris