2001-11-01 19:51:16

by Derek Glidden

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Subject: Linux 2.2 and 2.4 VM systems analysed


I've been following the 2.4 VM issues since the early 2.4-pre days. As
a "power user" and someone who uses Linux at work, the kernel's
stability is of great interest to me. Finally, I got sick of trying to
interpret the data from various sources on how well the 2.4 VM systems
perform overall and in comparison with each other and other systems. So
I ran my own tests against 2.4.12-ac6, 2.4.13, and 2.2.19 and wrote up
the results:

"An analysis of three Linux kernel VM systems"

http://www.nks.net/linux-vm.html

The conclusion in a nutshell is that yes, the 2.4 kernel VM systems
still have a few quirks to work out, but overall they are so
significantly better than the 2.2 VM that there really is no
comparison.

However, this "significantly better" conclusion is for certain
high-stress situations where the 2.2 VM apparently fails entirely, while
2.4 chugs along with barely a notice.

For overall end-user experience, 2.2 still "feels" better overall with
better interactive responsiveness under a varying set of loads even
though 2.4 really is faster at doing the actual work.

Comments, responses, suggestions welcome. Flames will be cheerfully
redirected to /dev/null.

--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
#!/usr/bin/perl -w
$_='while(read+STDIN,$_,2048){$a=29;$b=73;$c=142;$t=255;@t=map
{$_%16or$t^=$c^=($m=(11,10,116,100,11,122,20,100)[$_/16%8])&110;
$t^=(72,@z=(64,72,$a^=12*($_%16-2?0:$m&17)),$b^=$_%64?12:0,@z)
[$_%8]}(16..271);if((@a=unx"C*",$_)[20]&48){$h=5;$_=unxb24,join
"",@b=map{xB8,unxb8,chr($_^$a[--$h+84])}@ARGV;s/...$/1$&/;$d=
unxV,xb25,$_;$e=256|(ord$b[4])<<9|ord$b[3];$d=$d>>8^($f=$t&($d
>>12^$d>>4^$d^$d/8))<<17,$e=$e>>8^($t&($g=($q=$e>>14&7^$e)^$q*
8^$q<<6))<<9,$_=$t[$_]^(($h>>=8)+=$f+(~$g&$t))for@a[128..$#a]}
print+x"C*",@a}';s/x/pack+/g;eval

usage: qrpff 153 2 8 105 225 < /mnt/dvd/VOB_FILENAME \
| extract_mpeg2 | mpeg2dec -

http://www.cs.cmu.edu/~dst/DeCSS/Gallery/
http://www.eff.org/ http://www.anti-dmca.org/
http://www.sciencemag.org/cgi/content/full/293/5537/2028


2001-11-01 20:19:38

by Miquel van Smoorenburg

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Subject: Re: Linux 2.2 and 2.4 VM systems analysed

In article <[email protected]>,
Derek Glidden <[email protected]> wrote:
>For overall end-user experience, 2.2 still "feels" better overall with
>better interactive responsiveness under a varying set of loads even
>though 2.4 really is faster at doing the actual work.

Well today I switched my workstation (128 MB RAM, 256 MB swap)
over from 2.2.19 to 2.4.14-pre6. With mozilla, netscape, postgres,
perl, apache, X, gnome running I'm usually ~80 MB into swap.
With 2.2.19 you really don't want to do this. It's *slow*.
Early 2.4.x, ditto. But under 2.4.14-pre6, it flies. I'm happy.

Mike.
--
"Only two things are infinite, the universe and human stupidity,
and I'm not sure about the former" -- Albert Einstein.

2001-11-01 20:21:07

by Rik van Riel

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Subject: Re: Linux 2.2 and 2.4 VM systems analysed

On Thu, 1 Nov 2001, Derek Glidden wrote:

> "An analysis of three Linux kernel VM systems"
>
> http://www.nks.net/linux-vm.html


Nice, finally somebody has taken the time to do
some more rigourous testing ;)

I like this document...

regards,

Rik
--
DMCA, SSSCA, W3C? Who cares? http://thefreeworld.net/ (volunteers needed)

http://www.surriel.com/ http://distro.conectiva.com/

2001-11-01 23:42:31

by Kilobug

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Subject: Re: Linux 2.2 and 2.4 VM systems analysed

Derek Glidden wrote:

> "An analysis of three Linux kernel VM systems"
>
> http://www.nks.net/linux-vm.html

Very interesting article.

I think it'ld be great to ask many people with different hardware to do
the same kind of tests on different hardware to see the results.
I don't have the time time, but in a week or two I'll gladly run them on
my computers if this can help.
(I've an Athlon 1.2G with 512M of DDR and an UDMA-66 hard disk)
But it'll be more interesting if the test "protocol" is somehow
standardized. (and don't use commercial softwares, I don't own Oracle so
I can't run a test needinf Oracle).

A linux user that want to give a small amount back in exchange to the
great work you all do on Linux,

--
** Gael Le Mignot, Ing3 EPITA, Coder of The Kilobug Team **
Home Mail : [email protected] Work Mail : [email protected]
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"Software is like sex it's better when it's free.", Linus Torvalds

2001-11-02 14:16:12

by john slee

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Subject: Re: Linux 2.2 and 2.4 VM systems analysed

On Fri, Nov 02, 2001 at 12:42:00AM +0100, Kilobug wrote:
> standardized. (and don't use commercial softwares, I don't own Oracle so
> I can't run a test needinf Oracle).

oracle can be downloaded and legally used for personal non-commercial
purposes i believe

it doesn't make it "free" in the way this community generally uses the
term but it does let you test linux with a very popular application.

i hope you're not using a modem, it's a 3-cd download :-(

j.

--
R N G G "Well, there it goes again... And we just sit
I G G G here without opposable thumbs." -- gary larson