Go Back   HWBOT forum > >

Intel CPU Overclocking Blue team overclocking

A Favor to Ask: Skylake X and AVX512

User Tag List

Reply
Thread Tools Display Modes
  #1  
Unread 1 Week Ago
Mysticial Mysticial is offline
grunt bot
 
Join Date: Mar 2013
Location: United States
Posts: 103
Thanks: 3
Thanked 41 Times in 23 Posts
Mysticial
Default A Favor to Ask: Skylake X and AVX512

Right now, there are conflicting reports that this first line of Skylake X processors (based on the 10-core Skylake Purley LCC die) will not have full-throughput AVX512.If this is true, the current Skylake X processors will only be able to run AVX512 at half the speed as the server Xeons - IOW, no better than AVX2.

I want to definitively answer this question - both for myself and for anyone else looking to purchase a Skylake X processor for the purpose of AVX512.
Using the same FLOPs benchmark that discovered the Ryzen FMA bug, we should be able to find out if Skylake X has full-throughput, or half-throughput AVX512.

So my request for someone who has a Skylake X sample* to:
  1. Run the "2017-SkylakePurley" binary here: https://github.com/Mysticial/Flops/t...naries-windows**
  2. Do it at a fixed CPU frequency (to avoid the affects of Turbo Boost).
  3. Do it with HT enabled.
  4. Don't use an extreme overclock. If the chip has full-throughput AVX512, then those AVX512 instructions may produce more heat than any other benchmark you've ever run.
  5. Do it with a fully updated Windows 10. Or a recent version of Linux (like Ubuntu 17.04). This is needed to ensure that the OS has support for AVX512.
*I may be wrong, but I don't believe Skylake X benchmarks are under NDA anymore since there's already a gazillion HWBOT submissions and you can get access to the server variants on Google Cloud.

**The source code is also in that GitHub repo if you want to build it yourself. But be aware that if you need the Intel Compiler if you want to build the AVX512 binaries for Windows.

----------------

When you run the benchmark, I expect one of 3 things to happen:
  1. The binary crashes: This means that Windows 10 does not have support for AVX512 and we'll need to wait for that support.
  2. The numbers for 512-bit AVX are about the same as the 256-bit AVX: This means that the processor only supports half-throughput AVX512.
  3. The numbers for the 512-bit AVX are about 2x as that of the 256-bit AVX: This means that the processor supports full-throughput AVX512.

Here is what the benchmark looks like for a 32-core Skylake Purley system on Google Cloud running at 2.0 GHz with 2.5 GHz turbo:

Code:
Running Skylake Purley tuned binary with 1 thread...

Single-Precision - 128-bit AVX - Add/Sub
    GFlops = 15.904
    Result = 2.02376e+06

Double-Precision - 128-bit AVX - Add/Sub
    GFlops = 7.952
    Result = 1.00995e+06

Single-Precision - 128-bit AVX - Multiply
    GFlops = 15.936
    Result = 2.03498e+06

Double-Precision - 128-bit AVX - Multiply
    GFlops = 7.968
    Result = 1.00712e+06

Single-Precision - 128-bit AVX - Multiply + Add
    GFlops = 15.936
    Result = 1.69085e+06

Double-Precision - 128-bit AVX - Multiply + Add
    GFlops = 7.968
    Result = 841756

Single-Precision - 128-bit FMA3 - Fused Multiply Add
    GFlops = 31.872
    Result = 2.02868e+06

Double-Precision - 128-bit FMA3 - Fused Multiply Add
    GFlops = 15.936
    Result = 1.01782e+06

Single-Precision - 256-bit AVX - Add/Sub
    GFlops = 31.808
    Result = 4.06688e+06

Double-Precision - 256-bit AVX - Add/Sub
    GFlops = 15.936
    Result = 2.02901e+06

Single-Precision - 256-bit AVX - Multiply
    GFlops = 31.872
    Result = 4.06158e+06

Double-Precision - 256-bit AVX - Multiply
    GFlops = 15.936
    Result = 2.02013e+06

Single-Precision - 256-bit AVX - Multiply + Add
    GFlops = 31.872
    Result = 3.34696e+06

Double-Precision - 256-bit AVX - Multiply + Add
    GFlops = 15.936
    Result = 1.70441e+06

Single-Precision - 256-bit FMA3 - Fused Multiply Add
    GFlops = 63.744
    Result = 4.0399e+06

Double-Precision - 256-bit FMA3 - Fused Multiply Add
    GFlops = 31.872
    Result = 2.00801e+06

Single-Precision - 512-bit AVX512 - Add/Sub
    GFlops = 63.744
    Result = 8.11456e+06

Double-Precision - 512-bit AVX512 - Add/Sub
    GFlops = 31.872
    Result = 4.03949e+06

Single-Precision - 512-bit AVX512 - Multiply
    GFlops = 63.36
    Result = 8.0743e+06

Double-Precision - 512-bit AVX512 - Multiply
    GFlops = 31.872
    Result = 4.05014e+06

Single-Precision - 512-bit AVX512 - Multiply + Add
    GFlops = 63.744
    Result = 6.68723e+06

Double-Precision - 512-bit AVX512 - Multiply + Add
    GFlops = 31.872
    Result = 3.3739e+06

Single-Precision - 512-bit AVX512 - Fused Multiply Add
    GFlops = 127.488
    Result = 8.22848e+06

Double-Precision - 512-bit AVX512 - Fused Multiply Add
    GFlops = 63.744
    Result = 4.03805e+06


Running Skylake Purley tuned binary with 64 thread(s)...

Single-Precision - 128-bit AVX - Add/Sub
    GFlops = 683.36
    Result = 8.68179e+07

Double-Precision - 128-bit AVX - Add/Sub
    GFlops = 263.568
    Result = 3.35065e+07

Single-Precision - 128-bit AVX - Multiply
    GFlops = 527.616
    Result = 6.69453e+07

Double-Precision - 128-bit AVX - Multiply
    GFlops = 263.88
    Result = 3.34619e+07

Single-Precision - 128-bit AVX - Multiply + Add
    GFlops = 527.136
    Result = 5.58561e+07

Double-Precision - 128-bit AVX - Multiply + Add
    GFlops = 263.64
    Result = 2.79832e+07

Single-Precision - 128-bit FMA3 - Fused Multiply Add
    GFlops = 1056.77
    Result = 6.71142e+07

Double-Precision - 128-bit FMA3 - Fused Multiply Add
    GFlops = 528.336
    Result = 3.36188e+07

Single-Precision - 256-bit AVX - Add/Sub
    GFlops = 1054.14
    Result = 1.34076e+08

Double-Precision - 256-bit AVX - Add/Sub
    GFlops = 527.52
    Result = 6.68866e+07

Single-Precision - 256-bit AVX - Multiply
    GFlops = 1056.77
    Result = 1.34416e+08

Double-Precision - 256-bit AVX - Multiply
    GFlops = 527.664
    Result = 6.70251e+07

Single-Precision - 256-bit AVX - Multiply + Add
    GFlops = 1055.33
    Result = 1.12018e+08

Double-Precision - 256-bit AVX - Multiply + Add
    GFlops = 527.52
    Result = 5.59086e+07

Single-Precision - 256-bit FMA3 - Fused Multiply Add
    GFlops = 2110.08
    Result = 1.34046e+08

Double-Precision - 256-bit FMA3 - Fused Multiply Add
    GFlops = 1055.33
    Result = 6.69451e+07

Single-Precision - 512-bit AVX512 - Add/Sub
    GFlops = 2112.26
    Result = 2.68216e+08

Double-Precision - 512-bit AVX512 - Add/Sub
    GFlops = 1056
    Result = 1.34131e+08

Single-Precision - 512-bit AVX512 - Multiply
    GFlops = 2117.38
    Result = 2.69031e+08

Double-Precision - 512-bit AVX512 - Multiply
    GFlops = 1059.26
    Result = 1.34601e+08

Single-Precision - 512-bit AVX512 - Multiply + Add
    GFlops = 2118.14
    Result = 2.24393e+08

Double-Precision - 512-bit AVX512 - Multiply + Add
    GFlops = 1058.5
    Result = 1.12102e+08

Single-Precision - 512-bit AVX512 - Fused Multiply Add
    GFlops = 4242.43
    Result = 2.69409e+08

Double-Precision - 512-bit AVX512 - Fused Multiply Add
    GFlops = 2115.07
    Result = 1.34365e+08
This Skylake Purley system has full-throughput AVX512.
__________________
Reply With Quote
The Following User Says Thank You to Mysticial For This Useful Post:
Massman (1 Week Ago)
  #2  
Unread 1 Week Ago
Massman's Avatar
Massman Massman is offline
In the distance
 
Join Date: Jul 2006
Location: Taipei
Posts: 22,476
Thanks: 759
Thanked 1,047 Times in 522 Posts
Massman has a spectacular aura aboutMassman has a spectacular aura aboutMassman has a spectacular aura about
Send a message via MSN to Massman
Default Re: A Favor to Ask: Skylake X and AVX512

Fired off some emails
__________________
Where courage, motivation and ignorance meet, a persistent idiot awakens.

For all HWBOT community related questions, contact Christian Ney or Websmile. For any other questions, contact me at pieter@hwbot.org.
Reply With Quote
The Following User Says Thank You to Massman For This Useful Post:
Mysticial (1 Week Ago)
  #3  
Unread 3 Days Ago
Mysticial Mysticial is offline
grunt bot
 
Join Date: Mar 2013
Location: United States
Posts: 103
Thanks: 3
Thanked 41 Times in 23 Posts
Mysticial
Default Re: A Favor to Ask: Skylake X and AVX512

Bump. NDAs lifting today.

I'm most curious about the 7820X and the 7900X.

EDIT:

The reviews seems to indicate that the 6 and 8-core models will have half-throughput, and the 10-core model will have full-throughput. Microarchitecture Analysis: Adding in AVX-512 and Tweaks to Skylake-S - The Intel Skylake-X Review: Core i9 7900X, i7 7820X and i7 7800X Tested
__________________

Last edited by Mysticial; 3 Days Ago at 16:28.
Reply With Quote
  #4  
Unread 1 Day Ago
elmor's Avatar
elmor elmor is offline
transformer
 
Join Date: Nov 2006
Posts: 529
Thanks: 5
Thanked 574 Times in 134 Posts
elmor has a spectacular aura aboutelmor has a spectacular aura aboutelmor has a spectacular aura about
Default Re: A Favor to Ask: Skylake X and AVX512



Windows 10 1703 with Intel C++ redists installed.
Attached Images
File Type: png Capture.PNG (7.5 KB, 74 views)
__________________
Elmor's lab
Reply With Quote
  #5  
Unread 1 Day Ago
Mysticial Mysticial is offline
grunt bot
 
Join Date: Mar 2013
Location: United States
Posts: 103
Thanks: 3
Thanked 41 Times in 23 Posts
Mysticial
Default Re: A Favor to Ask: Skylake X and AVX512

Quote:
Originally Posted by elmor View Post


Windows 10 1703 with Intel C++ redists installed.
Thank you!

This is interesting though. The compiler seems to be trying to enforce that the computer has RDSEED instructions. But RDSEED was already available starting from Broadwell. I don't see why it would be missing from Skylake X unless it was explicitly disabled in the BIOS or something.

This might be a problem moving forward since the compiler forces these checks even though most programs won't use them anyway.

EDIT:

Is virtualization disabled in the BIOS? I'm reading around and it seems that some machines have all the crypto instructions disabled (AES-NI, RDRAND, and RDSEED) and it may be related to virtualization.
__________________

Last edited by Mysticial; 1 Day Ago at 17:45.
Reply With Quote
  #6  
Unread 19 Hours Ago
Mysticial Mysticial is offline
grunt bot
 
Join Date: Mar 2013
Location: United States
Posts: 103
Thanks: 3
Thanked 41 Times in 23 Posts
Mysticial
Default Re: A Favor to Ask: Skylake X and AVX512

I found a way to disable that check by the compiler and I've updated the binaries.

So if anyone is willing to try now, it should (hopefully) work regardless of whether RDSEED is enabled or not.

Thanks.
__________________
Reply With Quote
  #7  
Unread 12 Hours Ago
elmor's Avatar
elmor elmor is offline
transformer
 
Join Date: Nov 2006
Posts: 529
Thanks: 5
Thanked 574 Times in 134 Posts
elmor has a spectacular aura aboutelmor has a spectacular aura aboutelmor has a spectacular aura about
Default Re: A Favor to Ask: Skylake X and AVX512

Quote:
Originally Posted by Mysticial View Post
Thank you!

This is interesting though. The compiler seems to be trying to enforce that the computer has RDSEED instructions. But RDSEED was already available starting from Broadwell. I don't see why it would be missing from Skylake X unless it was explicitly disabled in the BIOS or something.

This might be a problem moving forward since the compiler forces these checks even though most programs won't use them anyway.

EDIT:

Is virtualization disabled in the BIOS? I'm reading around and it seems that some machines have all the crypto instructions disabled (AES-NI, RDRAND, and RDSEED) and it may be related to virtualization.
It was, but still get the same after enabling it.
__________________
Elmor's lab
Reply With Quote
  #8  
Unread 9 Hours Ago
Mysticial Mysticial is offline
grunt bot
 
Join Date: Mar 2013
Location: United States
Posts: 103
Thanks: 3
Thanked 41 Times in 23 Posts
Mysticial
Default Re: A Favor to Ask: Skylake X and AVX512

Quote:
Originally Posted by elmor View Post
It was, but still get the same after enabling it.
Would you be able to try with the latest binaries? I updated them last night.

As far as I can tell, I've removed the check. So it should get past that message and either run successfully or crash.

Thanks for you time.
__________________
Reply With Quote
  #9  
Unread 5 Hours Ago
l0ud_sil3nc3's Avatar
l0ud_sil3nc3 l0ud_sil3nc3 is offline
robot overlord
 
Join Date: May 2010
Location: UNITED STATES
Posts: 1,371
Thanks: 231
Thanked 229 Times in 121 Posts
l0ud_sil3nc3 has a spectacular aura aboutl0ud_sil3nc3 has a spectacular aura aboutl0ud_sil3nc3 has a spectacular aura about
Default Re: A Favor to Ask: Skylake X and AVX512

Quote:
Originally Posted by Mysticial View Post
Would you be able to try with the latest binaries? I updated them last night.

As far as I can tell, I've removed the check. So it should get past that message and either run successfully or crash.

Thanks for you time.
Works fine here with prior binaries will test later with latest.
__________________


Quote:
Originally Posted by sin0822 View Post
whats LOD?
Quote:
Originally Posted by Gunslinger View Post
If you can't beat 'em, report them! lol
Reply With Quote
  #10  
Unread 5 Hours Ago
Gunslinger's Avatar
Gunslinger Gunslinger is offline
robot overlord
 
Join Date: Dec 2007
Location: Decatur, AL
Posts: 1,584
Thanks: 168
Thanked 200 Times in 113 Posts
Gunslinger has a spectacular aura aboutGunslinger has a spectacular aura aboutGunslinger has a spectacular aura about
Send a message via MSN to Gunslinger
Default Re: A Favor to Ask: Skylake X and AVX512

Quote:
Originally Posted by l0ud_sil3nc3 View Post
Works fine here with prior binaries will test later with latest.
I don't believe you, send me your X299 gear so I can see first hand.
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 23:31.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Optimisation provided by DragonByte SEO (Lite) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright HWBOT 2004 - 2015
watch GOTS0701 usa news today