Retest: Re: New VM Testcase (2.4.18pre7 SWAPS) (2.4.17-rmap12b OK)

[Roger Larsson]

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!)
> >
> > ddteset.sh 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...

2.4.18pre7
	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)

2.4.17rmap12c
	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...

/RogerL

-- 
Roger Larsson
Skellefteå
Sweden