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Spectre/Meltdown Fixes and Their Effects on Processor Load & Speed


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#1 MDD1963

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Posted 08 March 2018 - 01:23 AM

If talking about new Ryzen APU's, there is not much discussion about hyper-threading v. multi-core difference because both Ryzen and Intel has SMT (Intel calls it Hyper threading). Also today AMD has lot cooler CPU's than Intel has. Ryzen also has much better GPU that can be used for calculations if software supports.

 

Also because Ryzen is immune to Meltdown bug, it's somewhat impossible to recommend any Intel CPU right now.

 

Granted, the Meltdown/Spectre fiasco was widely publicized, but, seemingly more of a hypothetical exploit, vice one actually afflicting/affecting users...

 

As for your claimed "20x slowdown" alluded to in another thread...just curious what that was based on....   "Twenty X"?

 

(Intel is probably squirming with the news of your rescinding recommending any Intel processors; I'm sure you were recommending Intel processors hand over fist before this hypothetical Meltdown/Spectre bug was known... right?)

 

As for the post -OS patch perforrrnance, a few games even showed a 1% improvement in framerates..... The sky has really fallen on Spectre!

 

I'll eagerly await your '20x' clarification, undoubtedly coming soon....

 

(Have you seen the leaked slide where AMD concedes it's new 2700X will be on average about 7% slower if using a GTX1080? Granted, the slide is unconfirmed, but the difference was up to almost 100 fps in some games. Can't imagine the difference being lower if a faster GPU such as a 1080Ti were used...)


Edited by britechguy, 09 March 2018 - 02:44 PM.
Split from thread asking about AMD vs. Intel processors for basic office computing tasks. While this may be an interesting conversation, it has nothing to do with the original question.

Asus Z270A Prime/7700K/32 GB DDR4-3200/GTX1060


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#2 Drillingmachine

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Posted 08 March 2018 - 10:02 AM

Granted, the Meltdown/Spectre fiasco was widely publicized, but, seemingly more of a hypothetical exploit, vice one actually afflicting/affecting users...
 
As for your claimed "20x slowdown" alluded to in another thread...just curious what that was based on....   "Twenty X"?
 
(Intel is probably squirming with the news of your rescinding recommending any Intel processors; I'm sure you were recommending Intel processors hand over fist before this hypothetical Meltdown/Spectre bug was known... right?)
 
As for the post -OS patch perforrrnance, a few games even showed a 1% improvement in framerates..... The sky has really fallen on Spectre!
 
I'll eagerly await your '20x' clarification, undoubtedly coming soon....
 
(Have you seen the leaked slide where AMD concedes it's new 2700X will be on average about 7% slower if using a GTX1080? Granted, the slide is unconfirmed, but the difference was up to almost 100 fps in some games. Can't imagine the difference being lower if a faster GPU such as a 1080Ti were used...)


Spectre/Meltdown fixes really hurts virtualization. There 20 times slower than before is quite common. Perhaps future program updates will get that lower but right now I experience eve bigger than 20 times slowdowns in certain cases.

Slide was proven to be fake.

#3 jarlmaster47

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Posted 08 March 2018 - 10:29 AM

 

Granted, the Meltdown/Spectre fiasco was widely publicized, but, seemingly more of a hypothetical exploit, vice one actually afflicting/affecting users...
 
As for your claimed "20x slowdown" alluded to in another thread...just curious what that was based on....   "Twenty X"?
 
(Intel is probably squirming with the news of your rescinding recommending any Intel processors; I'm sure you were recommending Intel processors hand over fist before this hypothetical Meltdown/Spectre bug was known... right?)
 
As for the post -OS patch perforrrnance, a few games even showed a 1% improvement in framerates..... The sky has really fallen on Spectre!
 
I'll eagerly await your '20x' clarification, undoubtedly coming soon....
 
(Have you seen the leaked slide where AMD concedes it's new 2700X will be on average about 7% slower if using a GTX1080? Granted, the slide is unconfirmed, but the difference was up to almost 100 fps in some games. Can't imagine the difference being lower if a faster GPU such as a 1080Ti were used...)


Spectre/Meltdown fixes really hurts virtualization. There 20 times slower than before is quite common. Perhaps future program updates will get that lower but right now I experience eve bigger than 20 times slowdowns in certain cases.

Slide was proven to be fake.

 

Cite your sources. Where is this 20x slowdown number coming from?



#4 britechguy

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Posted 08 March 2018 - 10:34 AM

All of the hype on Spectre and Meltdown, and what the fixes may or may not do with regard to performance, depends on who you want to believe.

 

https://duckduckgo.com/?q=spectre+meltdown+fix+performance+degradation


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#5 Drillingmachine

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Posted 08 March 2018 - 10:41 AM

Cite your sources. Where is this 20x slowdown number coming from?


Source is myself. After Microsoft released patches for Windows 10, Virtualbox is often 20 times slower (sometimes even more) and using some VM guests are totally unusable. WMWare is average around three times slower. That's average, not maximum slowdown.

Surprisingly those problems are because February Windows updates that clearly points to Meltdown/Spectre patches. Virtualbox unusable, WMWare average 3 times slower.

This is with AMD that is immune to Meltdown. Cannot even imagine what it would be with Intel...

All of the hype on Spectre and Meltdown, and what the fixes may or may not do with regard to performance, depends on who you want to believe.

https://duckduckgo.com/?q=spectre+meltdown+fix+performance+degradation


Constantly switching between user mode and kernel mode will cause slowdown. Bad slowdown. That's what virtual machines do and there it really hurts. I just hope future patches will disable Meltdown fix from AMD CPU's.

Edited by Drillingmachine, 08 March 2018 - 10:46 AM.


#6 Joe C

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Posted 09 March 2018 - 07:42 AM

 

Source is myself.

nuff said 'bout that.....

 

Microsoft provides a micro code update for Windows 10

https://support.microsoft.com/en-us/help/4090007/intel-microcode-updates

So the whole Spectre slow down thing is now a mute subject


Edited by Joe C, 09 March 2018 - 07:45 AM.


#7 Joe C

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Posted 09 March 2018 - 07:59 AM

AMD was stuck dead in the water for almost a decade, their Bull Dozer and chips following were no better than their Phenom chips. It wasn't until AMD came out with the Ryzen chips that got them back in the cpu game


Edited by Joe C, 09 March 2018 - 08:10 AM.


#8 Drillingmachine

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Posted 09 March 2018 - 11:22 AM

Source is myself.

nuff said 'bout that.....
 
Microsoft provides a micro code update for Windows 10

https://support.microsoft.com/en-us/help/4090007/intel-microcode-updates

So the whole Spectre slow down thing is now a mute subject


Question is not about providing update. Question is slowdown that update causes.

And that fix slows down Intel CPU's. Perhaps not as bad as Meltdown does but still.

AMD was stuck dead in the water for almost a decade, their Bull Dozer and chips following were no better than their Phenom chips. It wasn't until AMD came out with the Ryzen chips that got them back in the cpu game


Meltdown bug and fix for it makes Intel CPU's so slow that FX-series CPU's are faster when using virtualization.

So it took a while but finally FX CPUs overtook Intel chips.

#9 Joe C

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Posted 09 March 2018 - 11:58 AM

I'm sure that is your opinion... everybody does have one



#10 Drillingmachine

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Posted 09 March 2018 - 02:25 PM

Not exactly just opinion. Example from AWS https://www.theregister.co.uk/2018/01/09/meltdown_spectre_slowdown/ :
aws_cpu.jpg

 

0% CPU utilization transfers to 58% CPU utilization. Ouch.


Edited by Drillingmachine, 09 March 2018 - 02:25 PM.


#11 Joe C

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Posted 09 March 2018 - 04:02 PM

The latest fixes came out at the end of February,

Please try to use updated reviews to make your point valid

 

 Dated: 2/21/18

 

Intel last week published a new whitepaper explaining how Google's software-based fix for Variant 2 called Retpoline works. The search company found Retpoline doesn't cause the performance overhead that Intel's earlier mitigations did.

"There are a number of possible mitigation techniques for the branch target injection Spectre variant 2 exploit. The Retpoline mitigation technique presented in this document is resistant to exploitation and has attractive performance properties compared to other mitigations," Intel notes in the paper.

Link:

http://www.zdnet.com/article/intels-new-spectre-fix-skylake-kaby-lake-coffee-lake-chips-get-stable-microcode/


Edited by Joe C, 09 March 2018 - 04:18 PM.


#12 Drillingmachine

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Posted 10 March 2018 - 11:53 AM

That's Spectre variant 2 fix. AWS example above is only Meltdown fix.

#13 Joe C

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Posted 10 March 2018 - 04:52 PM

Read This:

 

Google had already patched Variant 1, also a Spectre attack, and Variant 3 aka Meltdown, by September, with Variant 2 standing out until December. These first two fixes had "no perceptible impact" on GCP or services like Gmail, Search, and Drive, but the fix for Variant 2 did.

That fix, called Retpoline, addresses Variant 2 of the two Spectre CPU attacks called 'branch target injection'. Variant 2 is considered by Microsoft and Google to be the trickiest speculative execution vulnerability to fix as it's the only one that does cause a significant hit on CPU performance.

link is in Post #11


Edited by Joe C, 10 March 2018 - 04:55 PM.


#14 Drillingmachine

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Posted 11 March 2018 - 03:37 AM

Read This:

Google had already patched Variant 1, also a Spectre attack, and Variant 3 aka Meltdown, by September, with Variant 2 standing out until December. These first two fixes had "no perceptible impact" on GCP or services like Gmail, Search, and Drive, but the fix for Variant 2 did.
That fix, called Retpoline, addresses Variant 2 of the two Spectre CPU attacks called 'branch target injection'. Variant 2 is considered by Microsoft and Google to be the trickiest speculative execution vulnerability to fix as it's the only one that does cause a significant hit on CPU performance.

link is in Post #11

 
Read bold part. No impact on certain workloads using Google services. That's very far from "no impact on every workload available".

Some benchmarks there. That's not worst case scenario. However that also illustrates Google's fix has perceptible impact https://www.phoronix.com/scan.php?page=article&item=clear-kpti-retpoline&num=5
 
Not surprising, performance penalty varies on workload. More I/O, more performance penalty. For heavy I/O situations:
 
https://www.techrepublic.com/article/meltdown-fixs-massive-overhead-will-slow-linux-systems-warns-netflix-engineer/
 

Changes to the Linux kernel to mitigate the impact of Meltdown have been found to slow systems, due to a performance overhead of between 1% and 800%.
The performance of systems that use a large number of syscalls or have high page fault rates is particularly severely affected.



#15 Joe C

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Posted 11 March 2018 - 06:44 AM

What your describing is not the type of things most peeps do. The Meltdown does not affect gaming to be that noticeable, And your still referring to old fixes that did affect performance, but not on the scale your stating. The new fixes do not affect performance like that. I'm not going to repeat myself anymore in this thread






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