Re: shared memory settings on MAC OS X

Hi,

>> I am trying to increase the amount of shared memory on my Mac OS 10.4
>> machine (i have 5 GB RAM installed), but without too much success.
>
> Weird, those same exact settings work fine for me. How up-to-date
> is your 10.4.x installation?

Ah, sorry, it's up to date, 10.4.10.

> The relevant part of /etc/rc in mine is
>
>
> if [ -f /etc/sysctl-macosxserver.conf ]; then
> awk '{ if (!index($1, "#") && index($1, "=")) print $1 }' <
> /etc/sysctl\
> -macosxserver.conf | while read
> do
> sysctl -w ${REPLY}
> done
> fi
> if [ -f /etc/sysctl.conf ]; then
> awk '{ if (!index($1, "#") && index($1, "=")) print $1 }' <
> /etc/sysctl\
> .conf | while read
> do
> sysctl -w ${REPLY}
> done
> fi
>
> sysctl -w kern.sysv.shmmax=4194304 kern.sysv.shmmin=1 kern.sysv.shmmni=32
> kern.\
> sysv.shmseg=8 kern.sysv.shmall=1024

Thanks for digging that out.

> So one obvious gotcha would be if you have a
> /etc/sysctl-macosxserver.conf file that sets 'em differently.

Good to know. Unfortunately I don't seem to have that file. Weird.

> The gotchas I know about in this area are:
>
> * The OSX kernel seems to lock down the shmem settings as soon as all
> five have been correctly specified via sysctl. This is why the sysctl
> done last in /etc/rc doesn't overwrite yours.

> * It's fairly draconian about what "correctly specified" is --- notably,
> at least some versions insist on shmmax being an exact multiple of the
> page size. But the numbers you quoted look OK.

I tried other numbers as well. Tiger wouldn't change that shmmax value from
4194304. Not sure what's going on there.

Thanks again,

- Maximilian Tyrtania | mty(at)fischerappelt(dot)de
fischerAppelt Kommunikation GmbH
Tucholskystr.18 | D-10117 Berlin | Germany
Tel. ++49-30-726146-728
http://www.fischerappelt.de

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