4 ms·

AMD's not doing a recall, it works decently enough for most applications. Their response is going to be "if it crashes your application, turn SMT off". Consid

by paulmd 9y ago

AMD's not doing a recall, it works decently enough for most applications. Their response is going to be "if it crashes your application, turn SMT off". Consider they didn't even do a recall when Phenom had a showstopping TLB bug, they shipped a BIOS patch that disabled TLB entirely. And remember, Epyc is on a new stepping of the silicon, it's possible this is already fixed on it. (Threadripper is not, however)

gruez 9y ago
> Their response is going to be "if it crashes your application, turn SMT off". it happens when SMT is disabled >Epyc is on a new stepping of the silicon, it's possible this is already fixed on it. (Threadripper is not, however) that's assuming they caught this bug, which i doubt is the case because it's only discovered now rather than being documented in the errata.
- dom0 9y ago
  I dunno, there were several issues in the SMT implementation publicized earlier, it is entirely possible that the root cause is the same or related.
- shizzlest 9y ago
  its possible they overlooked mentioning it in the errata but still fixed it with their stepping. dont give up last hope :)
Girlang 9y ago
This is why I buy Intel.
gigatexal 9y ago
No! I was going to buy threadripper for this very reason.
netheril96 9y ago
TLB, As Translation Lookaside Buffer? Won't memory access slow down dramatically if that is disabled?
- sveiss 9y ago
  Yup, and it did: http://techreport.com/review/13741/phenom-tlb-patch-benchmarked/3 http://techreport.com/review/13741/phenom-tlb-patch-benchmar...
- dom0 9y ago
  The Phenom bug was about the L2 TLB; the L1 TLB worked just fine. It still decreased performance significantly — about 5-20 % depending on workload.
dis-sys 9y ago
Epyc crashes quite often, see segfault screen shot. https://www.reddit.com/r/Amd/comments/6rmq6q/epyc_7551_mining_performance/ https://www.reddit.com/r/Amd/comments/6rmq6q/epyc_7551_minin...
grwthckrmstr 9y ago
As of now, threadripper is epyc silicon with 4 ccx disabled

by paulmd 9y ago

gruez 9y ago

> Their response is going to be "if it crashes your application, turn SMT off". it happens when SMT is disabled >Epyc is on a new stepping of the silicon, it's possible this is already fixed on it. (Threadripper is not, however) that's assuming they caught this bug, which i doubt is the case because it's only discovered now rather than being documented in the errata.

dom0 9y ago
I dunno, there were several issues in the SMT implementation publicized earlier, it is entirely possible that the root cause is the same or related.
shizzlest 9y ago
its possible they overlooked mentioning it in the errata but still fixed it with their stepping. dont give up last hope :)

Girlang 9y ago

This is why I buy Intel.

gigatexal 9y ago

No! I was going to buy threadripper for this very reason.

netheril96 9y ago

TLB, As Translation Lookaside Buffer? Won't memory access slow down dramatically if that is disabled?

sveiss 9y ago
Yup, and it did: http://techreport.com/review/13741/phenom-tlb-patch-benchmarked/3 http://techreport.com/review/13741/phenom-tlb-patch-benchmar...
dom0 9y ago
The Phenom bug was about the L2 TLB; the L1 TLB worked just fine. It still decreased performance significantly — about 5-20 % depending on workload.

dis-sys 9y ago

Epyc crashes quite often, see segfault screen shot. https://www.reddit.com/r/Amd/comments/6rmq6q/epyc_7551_mining_performance/ https://www.reddit.com/r/Amd/comments/6rmq6q/epyc_7551_minin...

grwthckrmstr 9y ago

As of now, threadripper is epyc silicon with 4 ccx disabled