[cfarm-users] GCC135/Power9 performance?

[Jeffrey Walton]

On Sun, Apr 12, 2020 at 5:11 AM Noah Misch <noah at leadboat.com> wrote:
>
> On Sun, Apr 12, 2020 at 12:03:13AM -0400, Jeffrey Walton via cfarm-users wrote:
> > GCC135 is a Power9 machine. Benchmarking on the machine shows
> > performance is off. For example, here are some numbers for AES in ECB
> > mode:
> >
> > GCC112 (Linux, ppc64le, 3.7 GHz, GCC 8.2):
> >    * 1.12 cpb, 2851 MB/s
> >
> > GCC119 (AIX, ppc64be, 4.1 GHz, GCC 8.2):
> >    * 0.54 cpb, 7242 MB/s
> >
> > GCC135 (Linux, ppc64le, 3.8 GHz, GCC 8.3):
> >    * 1.94 cpb, 1815 MB/s
>
> What source code did you use for this test?

I used Crypto++ (https://github.com/weidai11/cryptopp) for the test.

I also spoke with Andy Polyakov. OpenSSL is observing the same issue.

> > All algorithms show a similar slowdown. SHA is so slow I am
> > considering disabling in-core crypto for SHA and going back to the
> > integer unit.
> >
> > What is different about GCC135? Is the Power9 hardware really that slow?
>
> Generally no: https://www.ibm.com/downloads/cas/K90RQOW8
>
> Your source code or compiler may tune poorly for POWER9.  I assume you checked
> that gcc135 was lightly loaded at the time of your test.

It has been happening for at least a year.

Jeff