What are the ideal ranges for kern.ipc.shm*?

[Alberto Villa]

On Fri, Jul 12, 2013 at 5:24 AM, Chris H <bsd-lists at 1command.com> wrote:
> Greetings,
>  Over the years using the xfce4 desktop, I would occasionally receive
> SHM ERROR messages. As they never interfered (so's I could notice), I
> always put off attempting to track the cause down. However, now having
> performed a fairly major upgrade (~1yr since last), The error appears
> to greatly affect KDE4 (used to use kde3) applications I run within
> xfce4. The windows don't re-draw correctly, and I receive additional
> errors,as well:
> ...
> Resource id:  0x0
> X Error: BadDrawable (invalid Pixmap or Window parameter) 9
>   Major opcode: 62 (X_CopyArea)
>   Resource id:  0x0
> ...
> After much searching, it would appear to be related to the
> kern.ipc.shm* values.

$ cat /usr/ports/x11-toolkits/qt4-gui/pkg-message

Qt paint engine makes common use of shared memory. To avoid MIT-SHM
errors (i.e., blank windows), you probably need to raise shared memory
limits in loader.conf(5). The following should be safe values for the
KDE Plasma Desktop:

kern.ipc.shmall=32768
kern.ipc.shmmni=1024
kern.ipc.shmseg=1024
--
Alberto Villa, FreeBSD committer <avilla at FreeBSD.org>
http://people.FreeBSD.org/~avilla