[Omaha.pm] Self monitoring a perl scripts memory usage...

[Jay Hannah]

On Oct 21, 2009, at 2:17 PM, Dan Linder wrote:
> I have a script that usually maxes out around 100MB of memory (viewed
> via /proc/<PID>/status and watching the "VmPeak" value).
> In one test case, the complexity of the task grows, and the VmPeak
> tops out at over 300MB.  The server this is running on has "ulimit -v
> 256000" (roughly 256MB), so once the script passes 256MB it is killed.

Wow. That's a big process.  :)  You have to have all that in memory  
all at once? Can you cache out some of it or something?  
(Cache::FileCache?)

> Questions:
> 1: Is there a way to let a perl script query itself or the perl
> executable to determine how much memory it is currently using?  I'd
> like to log the highwater mark at exit so we can watch this over time,
> or possibly exit when "250MB" is used and give the user instructions
> on upping the limit in a config file after upping the ulimit value.

I'm not aware of a smart way. On Linux you could always run fork a "ps  
-ef" and find yourself.

irc.perl.org #perl-help might be helpful.

> 2: Can the signal be captured in a handler?  If I read chapter 17 of
> the OReilly "Learning Perl 3rd Edition", it says that they can't be
> trapped... :-(

If the OS sends the signal to perl then it's trivial to assign that  
signal to a subroutine and Do The Right Thing... In Linux, anyway. I  
don't know anything about Windows.  :)

    http://perldoc.perl.org/perlipc.html#Signals

HTH,

j