On 06/26/05 04:50 PM, Mikko Tyljrvi sat at the `puter and typed: > > <SNIP> > > This certainly does make sense, but I'm not sure I'm actually running > > short here. I have SYSVSEM in my kernel (as well as SYSVSHM and > > SYSVMSG), and the relevant sysctls are: > > > > kern.ipc.semmap: 30 > > kern.ipc.semmni: 10 > > kern.ipc.semmns: 60 > > kern.ipc.semmnu: 30 > > kern.ipc.semmsl: 60 > > kern.ipc.semopm: 100 > > kern.ipc.semume: 10 > > kern.ipc.semusz: 92 > > kern.ipc.semvmx: 32767 > > kern.ipc.semaem: 16384 > > Ok, looks like the default settings, which are often too low for > anything that makes heavy use of SYSV IPCs... > > > > > <root># ipcs -S > > seminfo: > > semmap: 30 (# of entries in semaphore map) > > semmni: 10 (# of semaphore identifiers) > > semmns: 60 (# of semaphores in system) > > semmnu: 30 (# of undo structures in system) > > semmsl: 60 (max # of semaphores per id) > > semopm: 100 (max # of operations per semop call) > > semume: 10 (max # of undo entries per process) > > semusz: 92 (size in bytes of undo structure) > > semvmx: 32767 (semaphore maximum value) > > semaem: 16384 (adjust on exit max value) > > > > <root># ipcs -s > > Semaphores: > > T ID KEY MODE OWNER GROUP > > s 65536 5432001 --rw------- pgsql pgsql > > s 65537 5432002 --rw------- pgsql pgsql > > s 65538 5432003 --rw------- pgsql pgsql > > ... such as databases :-) > > Have a look at /usr/ports/databases/postgresql80-server/pkg-message-server > for some sample settings. > > > Near as I can tell, this tells me I have at least 60 semaphores > > systemwide, 60 per id, 3 in use, none of which are being used by root > > (which is who I am running the test as). Shouldn't that leave 57 for > > the perl tests? > > Not necessarily. The SYSV IPCs is a particularly vicious piece of > poor engineering. > > Semaphores come in sets containing one or more semaphore. With your > settings you can have at most 10 sets, and a total of at most 60 > semaphores, and at most 60 per set, and at most 30... something else. > Also, at most 30 locks can be released in case a process unexpectedly > exits. > > Easy, right? > > Looks like you'll have to use "ipcs -sa" to see the "NSEMS" column, > which should tell you how many semaphores are in use. > > > How many does it need to open? > > No idea. Read the code or just raise the retarded limits by a lot. > Or try stopping postgres while running the tests. > > $.02, And then some.
You called this one right on the nose.
ipcs -sa showed each of the 3 pgsql processes were using 17 semaphores
(NSEMS column) wich really did cut things down. The
pkg-message-server file shed some light too.
I first shut down postgres, then ran the test, and everything worked
fine. Then I added the 3 lines below to /boot/loader.conf, then
rebooted and ran the tests again with postgres still running, and
everything worked fine again.
kern.ipc.semmns=240
kern.ipc.semume=40
kern.ipc.semmnu=120
So, I suspect I have enough semaphores for awhile now:
$ ipcs -S
seminfo:
semmap: 30 (# of entries in semaphore map)
semmni: 10 (# of semaphore identifiers)
semmns: 240 (# of semaphores in system)
semmnu: 120 (# of undo structures in system)
semmsl: 60 (max # of semaphores per id)
semopm: 100 (max # of operations per semop call)
semume: 40 (max # of undo entries per process)
semusz: 92 (size in bytes of undo structure)
semvmx: 32767 (semaphore maximum value)
semaem: 16384 (adjust on exit max value)
Thanks again.
Lou
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