Re: [ck] [ANNOUNCE] Interbench 0.27

[Con Kolivas <kernel@kolivas.org>]

On Thu, 4 Aug 2005 21:44, Gabriel Devenyi wrote:
> Hi Con,
>
> You must hate me by now...

No. A bug report is a bug report. I hate the fact that I coded up 2000 lines 
of code and am still suffering from a problem in the same 10 lines that I did 
in version .01. PEBKAC. 

> The "Gaming" benchmark has the same issue with nan coming out of the
> STDEV calculations, probably requires the same fix as before.

Anyway Peter Williams has promised to fix it for me (yay!).

> Secondly, the benchmarking of loops_per_ms is running forever, and I
> managed to determine where its happening.
>
> In calibrate loops you run a while loop and iterate to get 1000 for
> run_time, then you calculate it one more time to ensure it was right
> *however* you put a sleep(1) before that. It seems to seriously skew the
> results, as it consistently adds ~500 to run_time, as run_time is now
> 1500, it jumps back up to redo because of the goto statement, and runs
> the while loop again, continue ad nausium. I added some simple debugging
> output which prints run time at the end of each while loop, and right
> before the goto if statement, this is the output.

> The solution I used is of course to simply comment out the sleep
> statement, then everything works nicely, however your comments appear to
> indicate that the sleep is there to make the system settle a little,
> perhaps another method needs to be used. Thanks for your time!

I have to think about it. This seems a problem only on one type of cpu for 
some strange reason (lemme guess; athlon?) and indeed leaving out the sleep 1 
followed by the check made results far less reliable. This way with the sleep 
1 I have not had spurious results returned by the calibration. I'm open to 
suggestions if anyone's got one.

Cheers,
Con