09-24-2008
My version of truss does not have -c flag, or any other flag similar to the one I used with trace under Linux.
On Linux :
$ /sbin/sysctl -a |grep shm
... <snip error msgs>
vm.hugetlb_shm_group = 0
kernel.shmmni = 4096
kernel.shmall = 2097152
kernel.shmmax = 33554432
Q: Why would SHM parameters affect semaphore performance?
Also, just in case I ran this
$ /sbin/sysctl -a |grep sem
<snip error msgs>
kernel.sem = 250 32000 32 128
Last edited by migurus; 09-24-2008 at 08:55 PM..
Reason: added info
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LEARN ABOUT LINUX
sem_post
SEM_POST(3) Linux Programmer's Manual SEM_POST(3)
NAME
sem_post - unlock a semaphore
SYNOPSIS
#include <semaphore.h>
int sem_post(sem_t *sem);
Link with -lrt or -pthread.
DESCRIPTION
sem_post() increments (unlocks) the semaphore pointed to by sem. If the semaphore's value consequently becomes greater than zero, then
another process or thread blocked in a sem_wait(3) call will be woken up and proceed to lock the semaphore.
RETURN VALUE
sem_post() returns 0 on success; on error, the value of the semaphore is left unchanged, -1 is returned, and errno is set to indicate the
error.
ERRORS
EINVAL sem is not a valid semaphore.
EOVERFLOW
The maximum allowable value for a semaphore would be exceeded.
CONFORMING TO
POSIX.1-2001.
NOTES
sem_post() is async-signal-safe: it may be safely called within a signal handler.
EXAMPLE
See sem_wait(3).
SEE ALSO
sem_getvalue(3), sem_wait(3), sem_overview(7)
COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2009-03-30 SEM_POST(3)