Messages in this thread | | | Date | Mon, 7 Feb 2000 01:52:59 +0100 (CET) | From | Andrea Arcangeli <> | Subject | Re: 2.2.x Memory subsystem questions |
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On Wed, 19 Jan 2000, Mike Panetta wrote:
>Is there any way to get the 2.2.x kernels to have memory subsystem >performance similer to the 2.0.x kernels in low memory situations?
You may want to try this patch on the top of 2.2.14:
ftp://ftp.*.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.2/2.2.14aa6.gz
The system should stop to swapout then. After that you probably also want to tune by hand the VM checking the performance difference after executing something like this:
echo 10 > /proc/sys/vm/pagecache echo 10 > /proc/sys/vm/buffermem
(try also with 5 or 20, it mainly depends on what you are doing with the machine...) A value of 10 will forbid the VM to shrink the buffer cache and the page cache to less than 1.6mbyte. Thus you will lock in memory 3.2mbyte of ram with such defaults but you'll also know that you won't have to pagein for such 3.2mbyte of ram (you'll keep such information in cache ;). This by hand tuning is necessary only because the swapout behaviour in the VM is not smart enough in 2.2.x. I know how to make the VM smart enough (it's not very far from the point I just reach in the current 2.3.x). The other part that I have not yet implemented in the 2.3.x SMP threaded version, would be interesting only if you swapout all the time because you really haven't enough memory to run thus it's not high prio for now. Nevertheless I'll try to implement that as soon as I'll find the time ;).
Andrea
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