[Patch] Linpack-pc broken as a performance benchmark

[Hal Finkel]

----- Original Message -----
> 
> 
> The usual method of dealing with ever-changing computing power is to
> have the benchmark run for a fixed time and measure how many
> iterations were performed during that time.
> 

Agreed. Unfortunately, our test suite is not currently setup to handle that, and so the current state of things is useless. As I recall, we're planning to discuss this topic (how to best measure performance from the test suite) at the developers' meeting, and dealing with benchmarks that have good internal performance measures is certainly something worthwhile to discuss.

 -Hal

> 
> Yaron
> 
> 
> 
> 
> 
> 
> 2013/10/30 Hal Finkel < hfinkel at anl.gov >
> 
> 
> 
> ----- Original Message -----
> > 
> > On Oct 30, 2013, at 4:13 PM, Hal Finkel < hfinkel at anl.gov > wrote:
> > 
> > > ----- Original Message -----
> > >> Hi all,
> > >> 
> > >> SingleSource/Benchmark/Linpack is broken as a performance
> > >> benchmark.
> > >> It uses the time to execute a set of functions to determine the
> > >> time
> > >> to run another set of functions.
> > >> 
> > >> The attached patch fixes this by setting “ntimes” to arbitrary
> > >> 10000.
> > >> The benchmark then runs in about 30 secs on a recent mac.
> > > 
> > > 30 seconds sounds good to me. However, some of the embedded folks
> > > may complain ;) -- We should probably have it depend on whether
> > > SMALL_PROBLEM_SIZE is in effect or not. (You can add a
> > > preprocessor define in the makefile when SMALL_PROBLEM_SIZE is
> > > defined, and let that set it to be a factor of 10 smaller).
> > 
> > Sure,
> > 
> > most benchmarks I have seen seem to simply put a “#ifdef
> > SMALL_PROBLEM_SIZE” in the c source it self. So I did that.
> 
> Great, LGTM.
> 
> Thanks,
> Hal
> 
> 
> 
> > 
> > 
> 
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> 
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> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory