Messages in this thread |  | | Date | Sat, 05 Jan 2002 09:39:06 +0100 | From | Andreas Hartmann <> | Subject | Re: [2.4.17/18pre] VM and swap - it's really unusable |
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Stephan von Krawczynski wrote:
[...]
>>If you have applications, which doesn't >>access to much memory, you can't view the problems. >>If you access more than 1G (and you do not just copy, but rsync e.g.) >>and you have only 512MB of RAM, the machine swaps a lot with most actual >>2.4.-kernels (patches). >> > > Can you provide a simple and reproducible test case (e.g. some demo source), > where things break? I am very willing to test it here. >
It's easy - take a grown inn-newsserver-partition with reiserfs (*) (a lot of small files and a lot of directories), about 1,3 GB or more, and do a complete rsync to this partition to transport it somewhere else. But you have to do it with a existing target, no empty target, so that rsync must scan the whole target partition, too.
I don't like special test-programs. They seldom show up the reality. What we need is a kernel that behaves fine in reality - not in testcases. And before starting the test, take care, that most of ram is already used for cache or buffers or applications.
I did this test with several VM-patches and there are huge differences in swap consumption between them: 319MB with 2.4.17rc2 and 59MB with 2.4.17 oom-patch (max). It's more than a little difference :-).
Regards, Andreas Hartmann
(*) If I had DSL, I would send it to you (as tar.gz) - but with modem, it's a bit too much :-)! But your squid cache should be fine, too. It has a similar structure: a lot of small files and a lot of subdirectories. But I think, that your squid cache size isn't as high as my inn-partition.
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