How do I measure stack usage of a C/C++ program?

exit3219 · 01-22-2007, 09:37 AM

Hi.
I know I can profile / measure heap usage of programs with valgrind (massif). But how do I measure the maximum stack usage of a program (during a full run)? Google and the gcc manpage were of no help. I also looked in /proc/`pidof myprocess`/status but I can't understand much there.
I just want to know if what I'm asking for is possible. Technically, I only need to know if my program exceeds a certain limit (1MB). Is there a gcc switch to limit the stack size? What is the (default) stack limit on Linux systems anyway?
Any help would be greatly appreciated.

nnivanov · 01-22-2007, 09:51 AM

AFAIK, struct rusage which returns by wait3()/wait4 syscalls has one interesting field:

Code:

struct rusage
{
long ru_isrss;
}

Probably you should use wait4() for current pid with WNOHANG flag.

But I don't sure...

exit3219 · 01-22-2007, 10:18 AM

Thanks for replying.
I never used that function before. It's not even clear to me what it does (from the manpage). From what I can see from the getrusage manpage, though:

Code:

The above struct was taken from 4.3BSD Reno.  Not all fields are meaningful under Linux.  In linux 2.4  only  the
       fields  ru_utime, ru_stime, ru_minflt, and ru_majflt are maintained.  Since Linux 2.6, ru_nvcsw and ru_nivcsw are
       also maintained.

Looks like ru_isrss is not "meaningful" on Linux

nnivanov · 01-22-2007, 09:50 PM

wait3() is the same that wait() but with rusage. wait4() is the that waitpid() but also with rusage. Struct rusage just helps to get more information about exited process.

Here is two lines from my /usr/include/bits/resource.h in Linux:

/* Amount of stack memory used (kilobyte-seconds). */
long int ru_isrss;

Good luck!

exit3219 · 02-02-2007, 11:25 AM

I've found an easy way to limit stack usage in bash (for all processes started from the shell):
ulimit -Ss 1024
for limiting stack to 1MB. The default was 8MB on my machine.

This fits my needs for now. Thanks, anyway!