Em Tuesday 07 October 2008 13:05:44 Dan Nicholson escreveu:
>
> Whenever you do a getservbyname(), the glibc resolver has to parse out
> /etc/services. This happens when you use "http", and the resolver has
> to decide what port number to use. Likewise, when some program
> specifies "tcp", the glibc resolver has to parse /etc/protocols to
> decide what protocol number that corresponds to. So, cutting out the
> comments just makes the parsing faster. I saw a discussion of this a
> while ago on a fedora list, but I can't find the link now.
I follow the thread and found this forums before too.
>
> You can test this yourself with getent and then try again with a
> stripped down /etc/services (I didn't bother).
>
> $ time { for ((n = 0; n < 100; n++)); do getent services http
>
> >/dev/null; done; }
>
> real 0m0.098s
> user 0m0.033s
> sys 0m0.065s
>
> I happen to think the comments are more beneficial than any speedup,
> but that's just my preference.
>
> --
> Dan
I load the file on cache before the tests!
No Stripped
time { for ((n = 0; n < 100; n++)); do getent services http > /dev/null;
done }
real 0m0.110s
user 0m0.024s
sys 0m0.084s
Stripped
time { for ((n = 0; n < 100; n++)); do getent services http > /dev/null;
done }
real 0m0.106s
user 0m0.020s
sys 0m0.084s
Low difference! :(
--
Valter Douglas Lisbôa Jr.
Sócio-Diretor
Trenix - IT Solutions
"Nossas Idéias, suas Soluções!"
www.trenix.com.br
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