Re: [Bug-apl] 80 core performance results

[Juergen Sauermann]

Hi Elias,

thanks, already interesting. If you could loop around the core count:

for ((i=1; $i<=80; ++i)); do
 ./Parallel $i
 ./Parallel_OMP $i
done

then I could understand the data better. Also not sure if something
is wrong with the benchmark program. On my new 4-core with OMP I get
fluctuations from:

address@hidden ~/apl-1.3/tools $ ./Parallel_OMP 4
Pass 0: 4 cores/threads, 8229949 cycles total
Pass 1: 4 cores/threads, 8262 cycles total
Pass 2: 4 cores/threads, 4035 cycles total
Pass 3: 4 cores/threads, 4126 cycles total
Pass 4: 4 cores/threads, 4179 cycles total

to:

address@hidden ~/apl-1.3/tools $ ./Parallel_OMP 4
Pass 0: 4 cores/threads, 11368032 cycles total
Pass 1: 4 cores/threads, 4042228 cycles total
Pass 2: 4 cores/threads, 7251419 cycles total
Pass 3: 4 cores/threads, 3846 cycles total
Pass 4: 4 cores/threads, 2725 cycles total

The fluctuations with the manual parallel for are smaller:

Pass 0: 4 cores/threads, 87225 cycles total
Pass 1: 4 cores/threads, 245046 cycles total
Pass 2: 4 cores/threads, 84632 cycles total
Pass 3: 4 cores/threads, 63619 cycles total
Pass 4: 4 cores/threads, 93437 cycles total

but still considerable. The picture so far suggests that OMP fluctuates much
more (in the start-up + sync time) than manual with the highest OMP start-up above manual
and the lowest far below. One change on my  TODO list is to use futexes instead of mutexes
(like OMP does), probably not an issue under Solaris sunce futextes are linux-specific.

/// Jürgen


On 05/11/2014 04:23 AM, Elias Mårtenson wrote:

Here are the files that I promised earlier.

Regards,

Elias