Re: [squid-users] running squid on VERY low-end devices

From: Leonardo Rodrigues Magalhães <leolistas_at_solutti.com.br>
Date: Thu, 25 Sep 2008 09:30:10 -0300

John Doe escreveu:
>> Nice John, thanks very much for that !! Got it compiled and
>> running, no problem. Anyway, i found interesting that squid is
>> reporting a high average service time for this do-almost-nothing
>> external ACL (from cachemgr.cgi, external acl stats):
>> any hint on that ???
>>
>
> Did you compare with the perl version...?
>
> First, try it from the shell...
> Tested without the while loop and it looks fast (on my workstation):
> real 0m0.001s
> user 0m0.000s
> sys 0m0.001s
> With one fgets, I get in the worst case:
> real 0m0.002s
> user 0m0.000s
> sys 0m0.002s
>
> If it is also fast, maybe it is the fflush that is slow...
>
>

    Hi John,

    I think there's no problem with perl and C version. The problem
seems that i was trying to analyze average service timers with too few
requests and very low TTL (i was using 10 seconds). By the nature of
this external ACL, i simply cannot have very high TTLs, as i would have
in other cases. Anyway, after raising TTL to 30 seconds and having a lot
more requests, average time is getting low each time:

External ACL Statistics: verifica-ano
Cache size: 9
program: /etc/squid/verifica-ano.pl
number running: 3 of 3
requests sent: 1672
replies received: 1672
queue length: 0
avg service time: 95.48 msec

    (several minutes later)

External ACL Statistics: verifica-ano
Cache size: 9
program: /etc/squid/verifica-ano.pl
number running: 3 of 3
requests sent: 2761
replies received: 2761
queue length: 0
avg service time: 82.11 msec

    and those numbers are with the perl version !!! I'm pretty sure the
C and Perl versions wont have a very different response time. Both are
do-almost-nothing codes and i'm pretty sure both are extremely fast.

    Anyway, i'll use the C version because it has a lower memory
footprint. Each instance of microperl runs with 3.2% of memory (3.2% of
29860= 955Kb). Each instance of C version runs with 0.8% of memory (0.8%
of 29860=239Kb). All 3 instances of C version didnt use the memory of a
single microperl instance.

    These memory usage numbers, measured in Kbs, can be stupid when
analyzed for plenty-of-RAM machines .... but as i'm talking of a 32Mb
RAM device, they make the whole difference :)

-- 
	Atenciosamente / Sincerily,
	Leonardo Rodrigues
	Solutti Tecnologia
	http://www.solutti.com.br
	Minha armadilha de SPAM, NÃO mandem email
	gertrudes_at_solutti.com.br
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Received on Thu Sep 25 2008 - 12:30:26 MDT

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