> > I've got a lot of memory (some 380 megs), but what is VM pressure?
>
> VM pressure means that there is not enough free memory on the system...
> Allocators have to reclaim memory.
There's more than enough memory on the system, as far as I can see
[root@linuxserver ext2]# free
total used free shared buffers cached
Mem: 381500 378136 3364 0 3552 333348
-/+ buffers/cache: 41236 340264
Swap: 522104 11440 510664
> Basically you cannot simply expect an increase in readahead size to
> increase performance:
>
> 1) The files you created may not be sequential
Beleive me - they are! Created with 'dd' secuentially
> 2) The lack of memory on the system may be interfering in weird ways, and
> maybe _INCREASING_ the readahead may decrease performance.
Anyway - I beleive I should have seen some change by trying virtually any
value from 31 to 4095.
If the readahead is what I beleive it is, It'll read further out in the
file when a request comes. It looks like either this never happens, or the
next request doesn't 'know' how much is cached.
roy
-- Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCAComputers are like air conditioners. They stop working when you open Windows.
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This archive was generated by hypermail 2b29 : Fri Dec 07 2001 - 21:00:29 EST