Re: About these IPC parameters

Peter ...

Here is the 'latest and greatest' NOTES that one of the FreeBSD
guys has been working on for shared memory/semaphores ... not sure if it
helps or not, but I believe it was you that was working on "organizing
this"?

=============================
#####################################################################
# SYSV IPC KERNEL PARAMETERS
#
# Maximum number of entries in a semaphore map.
options SEMMAP=31

# Maximum number of System V semaphores that can be used on the system at
# one time.
options SEMMNI=11

# Total number of semaphores system wide
options SEMMNS=61

# Total number of undo structures in system
options SEMMNU=31

# Maximum number of System V semaphores that can be used by a single
process
# at one time.
options SEMMSL=61

# Maximum number of operations that can be outstanding on a single System
V
# semaphore at one time.
options SEMOPM=101

# Maximum number of undo operations that can be outstanding on a single
# System V semaphore at one time.
options SEMUME=11

# Maximum number of shared memory pages system wide.
options SHMALL=1025

# Maximum size, in bytes, of a single System V shared memory region.
options SHMMAX="(SHMMAXPGS*PAGE_SIZE+1)"
options SHMMAXPGS=1025

# Minimum size, in bytes, of a single System V shared memory region.
options SHMMIN=2

# Maximum number of shared memory regions that can be used on the system
# at one time.
options SHMMNI=33

# Maximum number of System V shared memory regions that can be attached to
# a single process at one time.
options SHMSEG=9
========================================

On Thu, 27 Jul 2000, Bruce Momjian wrote:

> > So, SEMMNI and SEMMNS seem to be the most promising settings to change.
> >
> > Is there any noteworthy relevance of some of the other parameters? I see
> > FAQ_BSDI talks about SEMUME and SEMMNU.
>
> I wrote FAQ_BSDI because it was not trivial to figure out how to modify
> those parameters. I figured other OS's either don't need to do it, or
> have an easier way of doing it.
>
> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> + If your life is a hard drive, | 830 Blythe Avenue
> + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
>

Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy
Systems Administrator @ hub.org
primary: scrappy(at)hub(dot)org secondary: scrappy(at){freebsd|postgresql}.org