time test

[Greg Louis]

On 20021123 (Sat) at 1807:40 -0500, David Relson wrote:

> For laughs, I built bogofilter with four different optimization 
> levels.  The compiler switches used were '-G' (no optimization), '-O1, 
> '-O2', and '-O3'.  bogofilter was run 1000 times on a test message.
> 
> 	  	  g	  O1	  O2	  O3
> user		18.17	15.69	15.05	14.89
> system 	 3.24	 3.40	 3.17	 3.11
> elapsed	21.44	19.32	18.23	18.00
> 
> It appears that maximum speed is about 1/7 (14%) better than worst code.
> 
> Notes: tests run on 500 mhz Pentium III with 256mb ram, kernel 
> linux-2.4.19-16mdk.

On reading the above, I decided "just for kicks" to try my
0.8.0-derived production version with -O3.  Variation from run to run
of the "time" command is about 2% so it's hard to be sure, but any two
adjacent runs (alternating between -O2 and -O3) show the -O3 version
(./bogofilter) being about 35-50 microseconds (~1%) faster:

# time for i in `seq 1 2000`; do bogofilter </root/testmsg; done

real 0m15.290s    user 0m10.650s    sys 0m4.610s

# time for i in `seq 1 2000`; do ./bogofilter </root/testmsg; done

real 0m15.218s    user 0m10.590s    sys 0m4.600s

That's on a 1.1 GHz (500 millihertz is a bit slow, no? :) PIII/mobile with
512Mb RAM / kernel 2.4.20-rc2-ac3.

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