2000-11-14 12:41:55

by Samium Gromoff

[permalink] [raw]
Subject: /proc tweaking

Hey people, i`ve got such a thought
not long ago:
all boxes are different, but the /proc/sys/vm
defaults are equal for every people, so there
is a good issue in getting more performance
from linux, just by making a way to autoadjust
these mysterious values according to amount of
RAM/swap and speed of CPU! Or this can be done
in userspace with an utility which look also
on the field of box` use (eg workstation, server etc...)
But who can make this better than the people who hack the kernel?
And i wonder why such a issue is not clearly covered? (maybe i`m making mistake?)
This can also be done for proc/sys/net/*...


2000-11-14 15:04:32

by Samium Gromoff

[permalink] [raw]
Subject: RE: /proc tweaking

on Tue, 14 Nov 2000 Arjan van de Ven wrote:
>In article <[email protected]> you wrote:
>> Hey people, i`ve got such a thought
>> not long ago:
>> all boxes are different, but the /proc/sys/vm
>> defaults are equal for every people, so there
>> is a good issue in getting more performance
>> from linux, just by making a way to autoadjust
>> these mysterious values according to amount of
>> RAM/swap and speed of CPU! Or this can be >done
>> in userspace with an utility which look also
>> on the field of box` use (eg workstation, >>server etc...)
>> But who can make this better than the >>people who hack the kernel?
>> And i wonder why such a issue is not >>clearly covered? (maybe
>>i`m making mistake?)
>> This can also be done for >>proc/sys/net/*...
>
>
>Take a look at powertweak. >http://powertweak.sourceforge.net
>Made by kernel people, for non-kernel people.

Maybe i were not enough exact, but i`ve meant
addition of some intelligence to tweaking /proc
e.g. something what automates tuning, not only
providing interface to such actions.
But after lookthru ptweaks source i realized
what its ONLY interface (to proc), and MAYBE
it does some PCI tuning (really intelligent
choices to advance system`s performance).
BTW powertweak is a port from unfamous MD,
therefore when it was created NO proc tuning
was in mind...

There is another argument, telling what doing autotune is ugly by design.... but thats another issue.

Sorry for poor english/lameness


2000-11-15 00:27:50

by Dave Jones

[permalink] [raw]
Subject: RE: /proc tweaking

Samium Gromoff wrote...

> >Take a look at powertweak. >http://powertweak.sourceforge.net
> >Made by kernel people, for non-kernel people.
> Maybe i were not enough exact, but i`ve meant
> addition of some intelligence to tweaking /proc
> e.g. something what automates tuning, not only
> providing interface to such actions.

If you check the version in CVS, you'll notice addition of
profiles which allow you to do just this.
"This is an Oracle server", "This is an Apache server" e.t.c.
(These profiles can also be combined for multi-purpose boxes)

> But after lookthru ptweaks source i realized
> what its ONLY interface (to proc), and MAYBE
> it does some PCI tuning

I assume you're referring to 0.1.17 codebase, which is no
longer getting actively developed. The version in CVS is due to
be released _very_ soon, and is notably improved.
- Profiles (as mentioned above)
- Each option now offers comprehensive advice.
- Other areas of tuning.
Notably CPU MSRs (with the /dev/msr interface), and
disk elevator adjustment.
- Several other new goodies.

And if it doesn't support your hardware, then hey, we accept patches.

> BTW powertweak is a port from unfamous MD

Bzzt, thanks for playing. I've no idea what program you're
referring to, a google-search for "MD /proc/sys" revealed
nothing relevant.

Just for the record, it started as the 2.2 `Tune PCI bridges'
feature moved to userspace named "TunePCI" (never released),
and then had a reimplementation of a tool called `proctune'
by Arjan van de Ven added to it. Only then did it get named
Powertweak-Linux.

Time passed, and eventually Arjan rewrote the /proc/sys
tuning code to use XML.

> There is another argument, telling what doing autotune is ugly

How do you propose that the kernel should "know" what role you
intend to use it for ? Answer : It shouldn't, it's a userspace
problem, best solved in userspace by a userspace tool.

regards,

davej.

--
| Dave Jones <[email protected]> http://www.suse.de/~davej
| SuSE Labs