6 ms·

> Gamers don't really care that ECC prevents one crash in years because they are used to frequent crashes already. I work on GPU drivers for one of those compa

by kimixa 5y ago

> Gamers don't really care that ECC prevents one crash in years because they are used to frequent crashes already. I work on GPU drivers for one of those companies. We regularly get reports and backtraces that cannot be reproduced, or "Cannot Happen" without some external factor (e.g. some other bit of code poking around our memory space). Often they're just silently dropped or ignored on the long tail of issues that nobody can get any traction on. My understanding is the stats from hyperscalers is that ECC correction events happen a lot more than "Common Knowledge" may imply - I wonder just what proportion of things that are blamed on software may actually be due to hardware issues like this? Again, without a significant change in the market (IE enough gamers start using ECC to actually be statistically relevant and comparing stability) this cannot really be tested, but I've wondered.

bcrl 5y ago
Except that anyone using Intel desktop CPUs pretty much can't use ECC thanks to marketing deciding that ECC is a market segmentation feature. The real way to make ECC happen industry wide is for OS vendors like Microsoft to make it a platform requirement. A no ECC, no boot policy would change things overnight. Sadly, we can't even get DRAM manufacturers to fix row hammer properly, so the likelihood of this happening is pretty much nil.
- wmf 5y ago
  You can use ECC by buying the Xeon version which is only slightly more expensive.
  - temac 5y ago
    Though the motherboards and ram modules are also harder to find and with far less choice. (and actually the processors are too, depending on your market)
    - sliken 5y ago
      Yes, sure, motherboards and CPUs have far less choices. But generally plenty for any normal use case. Motherboards and CPUs have a crazy number of flavors, none of which matter one whit for normal use cases. It's so bad motherboards are differentiating on the manliness of the heat sink design, lighting options, and the color of the motherboard.
- sliken 5y ago
  If people cared, they would buy ECC capable chips. In fact my desktop is a Xeon e3-1230v5, which as cheaper and slightly slower (3.4 vs 3.6 GHz or something) then the equivalent i7. It was $50 more for the motherboard and $100 more for the ram. I'm sure if the market flooded to ECC capable chips (the silicon is the same) Intel would sell them. So many people grumble, but I'm not really sure Intel should push ECC if desktops users aren't willing to pay a modest premium for it. Many cheer AMD, which does not disable ECC on desktop chips, but neither do they promise ECC will actually work. It's a confusing mess between physical capacity (ram increases by 16GB when you add a 16GB dimm), and the actual correction of errors and telling the OS about the event. Only on the EPYC does AMD test and certify that ECC will work.
  - bcrl 5y ago
    Your comments about AMD are not entirely true: AMD officially supports ECC in the Pro variants of their desktop CPUs / APUs. I'm currently using a Ryzen 3800X with ECC memory and EDAC reports that it's working. ASRock lists qualified ECC DIMMs for virtually all of their motherboards. It's more that it's a feature motherboard vendors can support if they want to rather than being a platform requirement. But yes, it is sad that AMD doesn't make it an officially supported feature of the platform.
    - theevilsharpie 5y ago
      > AMD officially supports ECC in the Pro variants of their desktop CPUs / APUs ECC is only officially supported on the Ryzen Threadripper PRO, and that's largely because it uses registered memory which will practically always have ECC capability. Regular Ryzen PRO CPUs have the same ECC support as non-PRO Ryzen CPUs: functional, but not validated by AMD. Ryzen PRO APUs have (non-validated) support for ECC, whereas non-PRO APUs don't support ECC at all.
    - sliken 5y ago
      Right, but sadly AMD Ryzen Pro aren't sold directly to consumers (well unless you buy grey market on ebay), even if they did there's no such thing as a Ryzen Pro motherboard, or a Ryzen Pro BIOS. Not to mention AMD has been slow to upstream various EDAC related kernel patches. It's not really a supported config, there's no guarantee it will work, no promise from AMD (other than it's not disabled), and you can't return a Ryzen CPU because the ECC doesn't work. Various tests from various reddit posts show that some vendors "qualify" ECC dimms as working (an inserted Dimm increases ram available), some correct bits but don't correctly tell the kernel, and others actually do correct and report. So it's basically just a big mess. I'd buy an Epyc, but sadly unlike Intel the premium for a "server" chip is huge, if you can find them anywhere near MSRP. I looked for a Epyc 7313p near MRSP (announced in March 2021) without luck and finally gave up and bought a Ryzen. With all that said, ASRock is from what I can tell the best AMD motherboard company to support ECC with AMD. I've got a ASRock X570D4U, other than it refusing to allow sharing a IPMI/BMC interface with the system, I'm pretty happy with it.
temac 5y ago
> My understanding is the stats from hyperscalers is that ECC correction events happen a lot more than "Common Knowledge" may imply - I wonder just what proportion of things that are blamed on software may actually be due to hardware issues like this? What is the order of magnitude of ECC correction events?
- wmf 5y ago
  https://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf https://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf
  - sliken 5y ago
    Looks like a good paper, but transistors have gotten quite a bit smaller since 2009, and voltages have gotten lower as well. So the energy required to flip a bit has shrunk quite a bit since 2009.

by kimixa 5y ago

bcrl 5y ago

Except that anyone using Intel desktop CPUs pretty much can't use ECC thanks to marketing deciding that ECC is a market segmentation feature. The real way to make ECC happen industry wide is for OS vendors like Microsoft to make it a platform requirement. A no ECC, no boot policy would change things overnight. Sadly, we can't even get DRAM manufacturers to fix row hammer properly, so the likelihood of this happening is pretty much nil.

wmf 5y ago
You can use ECC by buying the Xeon version which is only slightly more expensive.
- temac 5y ago
  Though the motherboards and ram modules are also harder to find and with far less choice. (and actually the processors are too, depending on your market)
  - sliken 5y ago
    Yes, sure, motherboards and CPUs have far less choices. But generally plenty for any normal use case. Motherboards and CPUs have a crazy number of flavors, none of which matter one whit for normal use cases. It's so bad motherboards are differentiating on the manliness of the heat sink design, lighting options, and the color of the motherboard.
sliken 5y ago
If people cared, they would buy ECC capable chips. In fact my desktop is a Xeon e3-1230v5, which as cheaper and slightly slower (3.4 vs 3.6 GHz or something) then the equivalent i7. It was $50 more for the motherboard and $100 more for the ram. I'm sure if the market flooded to ECC capable chips (the silicon is the same) Intel would sell them. So many people grumble, but I'm not really sure Intel should push ECC if desktops users aren't willing to pay a modest premium for it. Many cheer AMD, which does not disable ECC on desktop chips, but neither do they promise ECC will actually work. It's a confusing mess between physical capacity (ram increases by 16GB when you add a 16GB dimm), and the actual correction of errors and telling the OS about the event. Only on the EPYC does AMD test and certify that ECC will work.
- bcrl 5y ago
  Your comments about AMD are not entirely true: AMD officially supports ECC in the Pro variants of their desktop CPUs / APUs. I'm currently using a Ryzen 3800X with ECC memory and EDAC reports that it's working. ASRock lists qualified ECC DIMMs for virtually all of their motherboards. It's more that it's a feature motherboard vendors can support if they want to rather than being a platform requirement. But yes, it is sad that AMD doesn't make it an officially supported feature of the platform.
  - theevilsharpie 5y ago
    > AMD officially supports ECC in the Pro variants of their desktop CPUs / APUs ECC is only officially supported on the Ryzen Threadripper PRO, and that's largely because it uses registered memory which will practically always have ECC capability. Regular Ryzen PRO CPUs have the same ECC support as non-PRO Ryzen CPUs: functional, but not validated by AMD. Ryzen PRO APUs have (non-validated) support for ECC, whereas non-PRO APUs don't support ECC at all.
  - sliken 5y ago
    Right, but sadly AMD Ryzen Pro aren't sold directly to consumers (well unless you buy grey market on ebay), even if they did there's no such thing as a Ryzen Pro motherboard, or a Ryzen Pro BIOS. Not to mention AMD has been slow to upstream various EDAC related kernel patches. It's not really a supported config, there's no guarantee it will work, no promise from AMD (other than it's not disabled), and you can't return a Ryzen CPU because the ECC doesn't work. Various tests from various reddit posts show that some vendors "qualify" ECC dimms as working (an inserted Dimm increases ram available), some correct bits but don't correctly tell the kernel, and others actually do correct and report. So it's basically just a big mess. I'd buy an Epyc, but sadly unlike Intel the premium for a "server" chip is huge, if you can find them anywhere near MSRP. I looked for a Epyc 7313p near MRSP (announced in March 2021) without luck and finally gave up and bought a Ryzen. With all that said, ASRock is from what I can tell the best AMD motherboard company to support ECC with AMD. I've got a ASRock X570D4U, other than it refusing to allow sharing a IPMI/BMC interface with the system, I'm pretty happy with it.

temac 5y ago

> My understanding is the stats from hyperscalers is that ECC correction events happen a lot more than "Common Knowledge" may imply - I wonder just what proportion of things that are blamed on software may actually be due to hardware issues like this? What is the order of magnitude of ECC correction events?

wmf 5y ago
https://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf https://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf
- sliken 5y ago
  Looks like a good paper, but transistors have gotten quite a bit smaller since 2009, and voltages have gotten lower as well. So the energy required to flip a bit has shrunk quite a bit since 2009.