Re: wired memory

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

On Tue, Nov 10, 2020 at 05:26:26AM -0800, Chuck Silvers wrote:
> On Tue, Nov 10, 2020 at 11:40:08AM +0000, Patrick Welche wrote:
> > My 4 Nov -current/amd64 build box seems to be building slowly, with a lot
> > of "biowait", e.g. watching the RES of a cc1plus slowly crawl up to SIZE
> > at around 3M per 5s.
> > 
> > Is 10G of "Wired" normal? (32G RAM + 64G swap)
> > (lots of malloc(9) and no free(9)?)
> 
> kernel memory usage is not reported as "wired" memory.

I got that notion from:

https://www.netbsd.org/docs/internals/en/chap-memory.html#wired_memory

> > Memory: 3235M Act, 115M Inact, 10G Wired, 75M Exec, 2860M File, 2800M Free
> > Swap: 64G Total, 11G Used, 53G Free
> 
> no, 10GB wired memory out of 32GB total RAM is not a typical situation.
> could you send me the output of "ps aux" and "vmstat -m" ?

Thanks - sent off list

> with 11GB of swap in use, it's not surprising that the system would be
> very slow.

Part of the question is why it needs to swap... (where did the 10G go?)

> > it is "just" building...
> > 
> > Could kern.maxfiles = 108928 be an issue? (3404 default below)
> 
> do you mean that on the system that is slow, kern.maxfiles is 108928?
> that doesn't seem overly large for 32GB RAM.
> 
> I'm not sure what you mean by "3404 default below".

just that the box below had the default kern.maxfiles=3404 setting, but
as you say that shouldn't be too large, and without it, one sees complaints
of insufficient files.


> > Just looked at another amd64 box for comparison (also building - no swap):
> > 
> > Memory: 15G Act, 3820K Inact, 16M Wired, 44M Exec, 14G File, 135G Free
> > Swap: 
> 
> this system has a lot more RAM and most of it isn't even used,
> so I would expect this system to perform much better than the first one.

Yes, but also just 16M of "Wired" memory...


Cheers,

Patrick