
Power9 Benchmarks vs. Intel Xeon vs. AMD EPYC Performance on Debian Linux - rbanffy
https://www.phoronix.com/scan.php?page=article&item=power9-epyc-xeon&num=1
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throwaway84742
I’m more impressed by Xeon Gold vs EPYC perf. The fact that Power 9 is
currently slower on workloads that heavily benefit from hand-optimized code
specific to Intel CPUs should not really surprise anybody. It’s likely that
this code just uses a “portable”, slow implementation on Power9, just because
nobody has the systems to work with yet. Additionally it’s also likely that
most software in these tests can’t take advantage of such a huge number of
threads.

~~~
zrm
> I’m more impressed by Xeon Gold vs EPYC perf.

The hardware used in this benchmark isn't very well chosen. All the systems
have a different number of cores (Power 16, AMD 32, Intel 40), and the AMD
system has the additional disadvantage over the others of being 1P instead of
2P, which approximately halves the available cooling and correspondingly
limits clock speeds. The results aren't very surprising given that.

Making comparisons like this can make sense when one of the competitors
doesn't make an equivalent product, but they all _do_ make products with an
equivalent number of sockets and cores.

~~~
mping
I believe the fair comparison would be performance per dollar - comparing
similarly priced components. Same sockets and cores can have wildly different
costs.

~~~
zrm
Comparing like with like can give you a better idea of what's going on even if
the prices aren't the same. It's a matter of isolating the architecture from
the other factors. If a 40 core 2P Intel system is faster than a 32 core 1P
AMD system, you don't know if the difference is architectural or just the
extra cores and sockets, so you don't know whether to expect a 48 core 2P AMD
system to be faster or slower than the Intel system.

And the tested systems aren't equivalently priced here either.

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daxorid
In before questions of "why would I pay so much for such a slow machine" \-
the target market for Talos is not necessarily those who seek raw performance.

For many of us, having a workstation that is at least in the same rough range
of performance while _being free and clear of IME and PSP_ is worth the price
premium.

RISC V is slowly getting there, but for real work, this is a decent option for
us tinfoil hat crowd.

~~~
sigjuice
Sorry for the grim picture, but what is stopping RISC-V SoC makers from
bolting on their own IME and PSP nonsense?

~~~
IntelMiner
Presumably, the "tinfoil hat users" would just elect to buy a different board
without those features grafted on

It's an open design. So those additions would be an OEM decision

~~~
sigjuice
I find it very unlikely that an OEM will emerge that will suddenly cater to us
“tinfoil hat users”.

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twoodfin
In addition to all the other caveats, it's important to remember that Power9's
biggest market target is probably highly transactional, tens-of-thousands-of-
users applications (basically, databases of one flavor or another) where how
the system handles NUMA, cache coherency and atomics is far more important
than how fast it can churn through embarrassingly parallel video encoding
tasks.

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winkeltripel
Should have probably built/tested the comparison systems without SSDs, since
the POWER9 had an SAS disk in it.

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masmullin
Does the article give full system prices? Perhaps in my rush to the graphs I
missed them.

I'm interested to know the price:performance comparison of the systems (wrt
kernel compilation time)

~~~
sp332
You can price out the POWER system they tested here.
[https://secure.raptorcs.com/content/TL2WK2/purchase.html](https://secure.raptorcs.com/content/TL2WK2/purchase.html)
Remember to type in "2" for the quantity of 22-core CPU upgrades you want.
Looks like at least $9k.

Edit: whoops, the article ran against the dual 8-core version, not the 22-core
one. Looks like $10,600 as tested, with the 500GB HD, 256GB RAM, and
workstation graphics.

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gnufx
I nearly always find benchmark numbers useless because they don't have nearly
enough information about how they're run and what the profile is. It's
difficult to gain much understanding otherwise. (A classic case is
communication-sensitive programs without information on MPI parameters like
collective algorithms.)

Can someone comment on how any of these that are basically computational
behave -- e.g. memory pressure, FP density, threading? I can't immediately
find profile information, for instance, though I could derive it with some
effort.

Also, is there definitive information somewhere on the POWER9 SIMD
implementation (e.g. vector width), which I couldn't find when I last looked.

~~~
Y_Y
Did you have a look at [https://www.phoronix-test-
suite.com/](https://www.phoronix-test-suite.com/) ?

~~~
gnufx
Yes, although I looked again, and found some things I understand well. There's
certainly no profile information there, and they don't appear to be well-
specified at build/run time. Some don't seem useful, e.g. reference HPCG
basically reduces to STREAM.

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dmitrygr
A lot of these benchmarks (video and audio encode for example) have hand-coded
assembly or hand-coded functions full of sse/avx intrinsics for x86_64. I
doubt they do the equivalent for PPC64LE (yet) so the results aren't
surprising (or useful).

~~~
zepearl
But this shouldn't be the case at least for the PyBench and PHPBench
benchmarks, or am I wrong? I really didn't expect such a huge difference in
those single-threaded tests (especially taking into account the Power9 CPU
running at 3.8Ghz...).

~~~
dmitrygr
I generally avoid languages like Python and PHP, so I do not know for sure but
are they _still_ not JITted on x86?

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api
How much is this an artifact of better code optimization for x64 systems vs.
PPC? Before Power9 I was under the impression that PPC was dead, and so never
put any effort into optimizing anything for it. I imagine this is common.

~~~
fiddlerwoaroof
Power9 isn't PPC: PPC is a derivative of the Power architecture made for
Apple, Power9 is IBM's server architecture.

~~~
stonogo
Much like the current Intel architecture is amd64, "ppc64" or "ppc64le" (for
little-endian) is the name of the architecture, even for current POWER
products.

~~~
wolfgke
> Much like the current Intel architecture is amd64

Wrong. For x86-64 there exist two implementations, which are called by their
vendors AMD64 and Intel 64 (the latter was marketed by Intel under the name
EM64T for a long time, but now Intel seems to use the name "Intel 64").

These are not identical, though mostly compatible. If you want to have
examples where they differ, look at

> [http://sandpile.org/x86/opc_1.htm](http://sandpile.org/x86/opc_1.htm)

> [http://sandpile.org/x86/opc_2.htm](http://sandpile.org/x86/opc_2.htm)

for instructions marked with "Df64" and "F64" (for the meaning of Df64 and F64
cf.
[http://sandpile.org/x86/opc_enc.htm](http://sandpile.org/x86/opc_enc.htm)).
Another more subtle difference can be found at slide 141-142 (though better
start at slide 133) of

> [https://www.blackhat.com/docs/us-17/thursday/us-17-Domas-
> Bre...](https://www.blackhat.com/docs/us-17/thursday/us-17-Domas-Breaking-
> The-x86-ISA.pdf)

~~~
iforgotpassword
Irrelevant. ppc means "any power based/derived architecture". It's called
amd64 in many places where it simply means 64bit x86. Linux does, Microsoft
does.

~~~
fiddlerwoaroof
Not really, as I understand it, PPC is a fork made for consumer devices and
IBM independently maintained a somewhat different POWER architecture for its
servers.

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bhouston
Why is the Intel machine 2P and all others are 1P?

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mastax
> Those were the systems available for this initial round of testing

The POWER9 system is also 2P.

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walrus01
Power9 might be amazing but it is worthless to me until I can buy off the
shelf motherboards for it from one of the big ten taiwanese motherboard
manufacturers. This is the reason why x86-64 has been so successful.

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sspiff
I know this is about Power9, but these benchmarks really make me look forward
to a time when companies will be ditching these first gen AMD EPYC processors
on eBay for cheap. Good times are coming.

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walshemj
Well Ryzen2 is almost hear and Rome Eypc2 is going to be next year I believe.

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goisa
This benchmark is a joke. Those 3 cpus cannot be compared to eachother.

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felipesoc
Why?

