Running Some Fresh GCC 8.0 Compiler Benchmarks On AMD EPYC With "znver1"

[phoronix]

Phoronix: Running Some Fresh GCC 8.0 Compiler Benchmarks On AMD EPYC With "znver1"

As SUSE has been working in conjunction with AMD on more tuning for AMD Zen CPUs under the GCC compiler, here are some fresh benchmarks of the GCC 8 compiler code being tested on an AMD EPYC system...

http://www.phoronix.com/scan.php?page=news_item&px=GCC-8.0-znver1-20171030

[andrei_me]

C-Ray run almost instantly nowadays, I remember years ago when the best Intel hardware could go below 20s

[Steffo]

Wow! This looks promising!

[audir8]

I found this post while trying to figure out why there isn't a /dev/hwrng on my Ryzen system: https://patchwork.kernel.org/patch/9856707/

Some benchmarks for random/urandom/hwrng would be nice. Not sure if openssl, grcypt or bork would suffice.

[hubicka]

I am happy to see that tuning changes bring improvements to some benchmarks. The large change in scimark is caused by if conversion. There is conditional based on random value which needs to be converted to conditional move BTW.

Core tuning should also see improvements in autovectorization and instruction selection.

[Michael]

I am happy to see that tuning changes bring improvements to some benchmarks. The large change in scimark is caused by if conversion. There is conditional based on random value which needs to be converted to conditional move BTW.

Core tuning should also see improvements in autovectorization and instruction selection.

Is there any other particular benchmarks where you have found interesting znver1 results with your tuning? Thanks!

[hubicka]

Is there any other particular benchmarks where you have found interesting znver1 results with your tuning? Thanks!

There is large improvement on facerec from spec2000, fotonik (for changes not merged yet) from spec2017 and some of polyhendron benchmarks that I remember offhand

[dxxvi]

Will there be znver2, 3, 4, ...?

[mlau]

Is there any other particular benchmarks where you have found interesting znver1 results with your tuning? Thanks!

How do the changes compare to "-mtune=broadwell" ?

[tajjada]

Will there be znver2, 3, 4, ...?

Likely yes.

znver1 is for first-generation "zen" cpus, aka the Ryzen/Threadripper/EPYC cpus that were released this year. AMD will likely make improved second-generation "zen" cpus in a year or two. Then, GCC will probably add a znver2 option for them.

This is similar to the support for AMD's previous architecture. GCC has the bdver1 option to support the first-gen Bulldozer CPUs (came out in 2012 IIRC). Then, there is bdver2 for second-generation Bulldozer (aka "Piledriver") and so on.