posix ipc message queue Post: 302072087

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Operating Systems HP-UX posix ipc message queue Post 302072087 by Perderabo on Thursday 27th of April 2006 09:36:22 AM

04-27-2006

Administrator Emeritus

Quote:

Originally Posted by cadanir

man mmap() says that HP-UX may or may not call shmat() to access shared memory... of course this doesn't help me much... and says that the max shareable mem size is 1.75 GBytes.

The language I see is "There may be implementation-dependent limits on the number of memory regions that can be mapped (per process or per system). If such a limit is imposed, whether the number of memory regions that can be mapped by a process is decreased by the use of shmat() is implementation-dependent." That is different than claiming mmap calls shmat. Anyway, shared memory has nothing at all to do with message queues.

Quote:

Originally Posted by cadanir

But I still don't know why I cannot go beyond 900 MB... for my posix queues.

According to the mq_open man page: "If attr is NULL, the message queue is created with default attributes - MQ_MAXMSG and MQ_MSGSIZE (defined in sys/mqueue.h) If attr is non-NULL and the message queue mq_maxmsg and mq_msgsize attributes are set to the values of the corresponding members in the mq_attr structure referred to by attr."

Since you're not happy with the default size, you are specifying a different size, right? What values are you using for mq_maxmsg and mq_msgsize?

Perderabo

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LEARN ABOUT DEBIAN

ipcs

IPCS(1) 							   User Commands							   IPCS(1)

NAME

       ipcs - provide information on ipc facilities

SYNOPSIS

       ipcs [-asmq] [-tclup]
       ipcs [-smq] -i id
       ipcs -h

DESCRIPTION

       ipcs provides information on the ipc facilities for which the calling process has read access.

       The -i option allows a specific resource id to be specified.  Only information on this id will be printed.

       Resources may be specified as follows:

       -m     shared memory segments

       -q     message queues

       -s     semaphore arrays

       -a     all (this is the default)

       The output format may be specified as follows:

       -t     time

       -p     pid

       -c     creator

       -l     limits

       -u     summary

SEE ALSO

       ipcrm(1), ipcmk(1)

CONFORMING TO

       The  Linux  ipcs  utility is not fully compatible to the POSIX ipcs utility.  The Linux version does not support the -b and -o options, but
       does support the -l and -u options not defined by POSIX. The portable application shall not use the -a, -b, -o, -l, and -u options.

AUTHOR

       krishna balasubramanian (balasub@cis.ohio-state.edu)

AVAILABILITY

       The ipcs command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

util-linux							   February 2008							   IPCS(1)