Subject: Re: LFS performance and kern.maxvnodes
To: Blair Sadewitz <>
From: Adam Hamsik <>
List: tech-kern
Date: 09/11/2007 13:15:47
Hash: SHA1

On Sep 11, 2007, at 3:46 AM, Blair Sadewitz wrote:

> I was about to propose something like this.  I don't recall what's in
> the guide, but I use pstat -T to check the number of available vnodes.
> There are many different ways this could be set better by default.
> I'm still formulating how I think this should be done, but IMHO
> maxusers is a bit archaic.  Is it so sacrosanct that we couldn't
> implement something else to make tuning NetBSD more intuitive for the
> "average" user?  It's always seemed odd to me to base tuning of vital
> system parameters upon some constant named something so abstruse that
> our documentation must clarify it in order for anyone to ever hazard a
> guess as to what it really does!
> How about raising the default at least on platforms where memory is
> usually plentiful, e.g. amd64?  If someone's using the amd64 port in,
> for example, an embedded application with little memory, presumably
> this user would already be proactively tuning the system.
> On the other hand, there are surely more elegant [and complex] ways to
> go about this.  We could have it scale by default along with other vm
> parameters, etc.
How is this self tuning mechanism done in other operating systems ?
Something like self workload tuning would be great.

I see 2 ways to do this:

1) Create kernel thread for monitoring in kernel data/statistics and  
tune uvm/vnode/ other option appropriate to them.

2) Create userspace daemon for monitoring and that daemon will use  
sysctl to tune kernel parameters.

It would be good if will we have some conclusion here.

Any better/ more concrete suggestions  ?

- -----------------------------------------
Adam Hamsik
icq: 249727910

Proud NetBSD user.

We program to have fun.
Even when we program for money, we want to have fun as well.
~ Yukihiro Matsumoto

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