[Beowulf] Theoretical vs. Actual Performance
pbisbal at pppl.gov
Thu Feb 22 16:19:16 PST 2018
Thanks for the link. Based on that, they should be pretty close in
performance, and mine are not, so I must be doing something wrong with
my OpenBLAS build. Since ACML is dead, I was hoping I could use OpenBLAS
On 02/22/2018 06:01 PM, Joe Landman wrote:
> ACML is hand coded assembly. Not likely that OpenBLAS will be much
> better. Could be similar. c.f.
> On 02/22/2018 05:48 PM, Prentice Bisbal wrote:
>> Just rebuilt OpenBLAS 0.2.20 locally on the test system with GCC
>> 6.1.0, and I'm only getting 91 GFLOPS. I'm pretty sure OpenBLAS
>> performance should be close to ACML performance, if not better. I'll
>> have to dig into this later. For now, I'm going to continue my
>> testing using the ACML-based build and revisit the OpenBLAS
>> performance later.
>> On 02/22/2018 05:27 PM, Prentice Bisbal wrote:
>>> So I just rebuilt HPL using the ACML 6.1.0 libraries with GCC 6.1.0,
>>> and I'm now getting 197 GFLOPS, so clearly there's a problem with my
>>> OpenBLAS build. I'm going to try building OpenBLAS without the
>>> dynamic arch support on the machine where I plan on running my
>>> tests, and see if that version of the library is any better.
>>> On 02/22/2018 09:37 AM, Prentice Bisbal wrote:
>>>> In your experience, how close does actual performance of your
>>>> processors match up to their theoretical performance? I'm
>>>> investigating a performances issue on some of my nodes. These are
>>>> older systems using AMD Opteron 6274 processors. I found literature
>>>> from AMD stating the theoretical performance of these processors is
>>>> 282 GFLOPS, and my LINPACK performance isn't coming close to that
>>>> (I get approximately ~33% of that). The number I often hear
>>>> mentioned is actual performance should be ~85%. of theoretical
>>>> performance is that a realistic number your experience?
>>>> I don't want this to be a discussion of what could be wrong at this
>>>> point, we will get to that in future posts, I assure you!
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