[OT] finding memory hungry bits of my code

[Dave Hodgkinson]

On 9 Apr 2009, at 15:08, Edmund von der Burg wrote:

> 2009/4/9 Andy Armstrong <andy at hexten.net>:
>> That sounds as if it could just be Perl getting up to cruising  
>> (memory)
>> altitude. Perl isn't especially keen on giving memory back to the  
>> OS once
>> it's used it; instead it keeps it hanging around and uses it to  
>> satisfy
>> future allocations.
>
> Perhaps you're right - but our cruising altitude would seem to be very
> high: our biggest processes according to top:
>
>  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 2050 web       15   0  126m 112m 5624 S    0  1.4   0:21.66
> /usr/sbin/apache-perl

That's not scary. The Stas Bekman's mod_perl guide has lots of good
stuff in there. But two rules:

1. Preload everything you can in startup.pl. There are tricks to finding
odd stuff you didn't think was obvious.

2. Have a proxy on the front, raise the accept queue and limit  
MaxClients
to something that will max your CPU and no more. No DoS, memory use is
constrained and it eases the load on your database.

Talk to Leo, we learned all this from scratch at EMAP *way* back in the
day when 256M was more than you'd ever need...


-- 
Dave Hodgkinson                                MSN: davehodg at hotmail.com
Site: http://www.davehodgkinson.com                  UK: +44 7768 490620
Blog: http://davehodg.blogspot.com
Photos: http://www.flickr.com/photos/davehodg