topic Memory utilization - glance vs. ps in Operating System - HP-UX

Memory utilization - glance vs. ps

Bret S — Wed, 21 May 2008 22:49:24 GMT

Glance reports 80% of my 2GB RAM is utilized. However, when I run:
UNIX95= ps -eo vsz,user,comm,args

And add up all the vsz numbers, I come out to about 307 MB used. According to the man page, vsz is in kb, so I assume I'm using the right metrics.

Re: Memory utilization - glance vs. ps

James R. Ferguson — Wed, 21 May 2008 23:05:20 GMT

Hi Bret:

The 'ps' output for 'vsz' is in *pages*:

# getconf PAGESIZE
4096

...so there is the first metric needed to obtain memory in bytes.

Also, 'ps' does *not* consider memory-mapped files or shared memory in its reporting.

Regards!

...JRF....

Re: Memory utilization - glance vs. ps

Emil Velez — Thu, 22 May 2008 12:30:44 GMT

Glance and measureware are always correct. They use a kernel interface to read its data which is specific to HPUX or the other OSs it is ported to.

As was previously mentioned glance includes all pages of a process and shared libraries and shared memory is not counted in ps.