Subject: Re: Configuring memory parameters for large network-based services
To: Jason Thorpe <>
From: Michael Graff <>
List: tech-kern
Date: 03/22/1999 12:38:31
Jason Thorpe <> writes:

>  > > (1)  What controls how much memory the pool system can use?
>  > > 
>  > 	It looks like its still dependent on NMBCLUSTERS
>  > 	arch/XXX/XXX/machdep.c defined the mb_map size in terms of
>  > 	VM_MBUF_SIZE, which is defined as a multiple of NMBCLUSTERS.
> Correct.

So, if I want to increase this limit to, say, 64M of kernel memory, I
can do this with

That is, what units is this in?  I'm guessing 2048 (cluster size)

also, how does that interact with NKMEMCLUSTERS=?

>  > 	options         NMBCLUSTERS=4096 or some suitable large number.

This is the number I have now, and it runs out of memory pretty fast.

When looking at the memory stats, the "Memory statistics by type" has
a limit of 19661K.  Does this mean the pool system gets up to that
much space?  I don't mind giving the kernel 1/4th of my ram if it
makes it able to handle a few thousand connections, but I'd rather not
throw 64M at it then find out it won't help.