Re: 2.4.23aa2 (bugfixes and important VM improvements for the highend)

[Andrew Morton]

"Martin J. Bligh" <mbligh@xxxxxxxxxxx> wrote:
>
> > We can write a testcase ourself, it's pretty easy, just create a 2.7G
> > file in /dev/shm, and mmap(MAP_SHARED) it from 1k processes and fault in
> > all the pagetables from all tasks touching the shm vma. Then run a
> > second copy until the machine starts swapping and see how thing goes. To
> > do this you need probably 8G, this is why I didn't write the testcase
> > myself yet ;).  maybe I can simulate with less shm and less tasks on 1G
> > boxes too, but the extreme lru effects of point 3 won't be visibile
> > there, the very same software configuration works fine on 1/2G boxes on
> > stock 2.4. problems showsup when the lru grows due the algorithm not
> > contemplating million of dirty swapcache in a row at the end of the lru
> > and some gigs of free cache ad the head of the lru. the rmap-only issues
> > can also be tested with math, no testcase is needed for that.
> 
> I don't have time at the moment to go write it at the moment, but I can certainly run it on large end hardware if that helps.

I think just

	usemem -m 2700 -f test-file -r 10 -n 1000

will do it.  I need to verify that.

http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz
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