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SubjectRetest: Re: New VM Testcase (2.4.18pre7 SWAPS) (2.4.17-rmap12b OK)
On Tuesdayen den 5 February 2002 01.36, Ed Tomlinson wrote:
> On February 4, 2002 05:24 pm, Roger Larsson wrote:
> > When examining Karlsbakk problem I got into one quite different myself.
> >
> > I have a 256MB UP PII 933 MHz.
> > When running the included program with an option of 200
> > (serving 200 clients with streaming data á 10MB... on first run
> > it creates the data, from /dev/urandom - overkill from /dev/null is ok!)
> >
> > 200
> > [testcase initially written by Roy Sigurd Karlsbakk, he does not get
> > into this - but he has more RAM]
> >

I rerun the testcases, this time the 2.4.18-pre8 did not go as deep - and
survived. But had worse performance - then I remembered... I had added
file readahead. Retested again - it still survived...

echo "file_readahead:255"> /proc/ide/hda/settings

The results from all tested kernels standard and with readahead follows...

start: with 'bi' at 12000
after awhile 'bi' hovers at 7000-9000 (sporadic swap outs)
after yet some time it starts to swap in too - but without performance loss

2.4.18pre7 with file_readahead:255
start: bi at 15000-18000
after awhile heavy swap out: 600(!)-10000
after yet some time, now with swap in too: 1000-6000

2.4.18pre7 w. Ed Tomlinsons patch
start: bi at 12000
stays at: 9000-12000
more swapout causes throughput loss: 5000-9000
but finally stabilizes at 7000-10000

2.4.18pre7 w. Ed Tomlinsons patch and file_readahead
start: bi at 15000-23000
rather soon ends up in both swapping in and out...
(about the same throughput at 2.4.18pre7)

during the whole testrun: bi at 10000-12000
exept for some short dips downto at most 8000

2.4.17rmap12c with file_readahead
during whole testrun: bi at 20000-23000
short dips downto 16000 (once 9000)

This should be a picture, but... some other day...


Roger Larsson
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