From owner-freebsd-questions  Sat Feb 17 21:18:40 2001
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Date: Sun, 18 Feb 2001 16:17:34 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: cjclark@alum.mit.edu
Cc: Cliff Sarginson <cliff@raggedclown.net>,
	Peter Pentchev <roam@orbitel.bg>, Artem Koutchine <matrix@ipform.ru>,
	questions@FreeBSD.ORG
Subject: Re: Efficiency [Was: Re: rpc.statd attack]
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[security removed from cc list]

On Sat, 17 Feb 2001, Crist J. Clark wrote:

> On Fri, Feb 16, 2001 at 03:03:44PM +0000, Cliff Sarginson wrote:
> 
> [snip]
> 
> > As you can see makes all the difference :)
> > But this is under Solaris ...
> >  
> > $ time rpcinfo -p | egrep -e 'udp.*status$' | awk '{print $4}'
> > 32790
> > 
> > real    0m0.12s
> > user    0m0.04s
> > sys     0m0.07s
> >   
> > $ time rpcinfo -p | awk '($3 == "udp") && ($5 == "status") {print $4 }'
> > 32790
> > 
> > real    0m0.11s
> > user    0m0.05s
> > sys     0m0.04s
> 
> Shocking. rpcinfo takes the same amount of time to run in both
> examples. You are not incuding the awk's and grep's in your
> measurements.

This is not clear, and probably isn't true, since the above doesn't
use time(1) to do the timing.

> ITYM,
> 
>   $ rpcinfo -p | time  egrep -e 'udp.*status$' | time awk '{print $4}'
>   996
>           0.05 real         0.00 user         0.00 sys
>           0.04 real         0.00 user         0.00 sys
> 
>   $ rpcinfo -p | time awk '($3 == "udp") && ($5 == "status") {print $4 }'
>   996
>           0.03 real         0.00 user         0.00 sys

Note the different format produced by time(1) with no options.  `time -p'
would produce ugly multi-line output, but not compatibly ugly with the
above.

The above might be produced by bash-2's `time' keyword.  One of the many
incompatibilities of bash-2's `time' is that it times whole pipelines.
It is so incompatibile that I upgraded from bash-2 to bash-1 just to avoid
it.  I was most annoyed by it breaking redirection, e.g.,
"time make world >world.log 2>&1" prints the time on the terminal, not in
world.log.  In bash-2, `time' is a keyword, not a builtin, so it can't even
be declared away by making it a function.

Bruce



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