Messages in this thread | | | From | "Luck, Tony" <> | Subject | RE: [PATCH] RAS/CEC: Reduce default threshold to offline a page to "2" | Date | Tue, 28 Jun 2022 16:51:49 +0000 |
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>> Existing default is 1023 ... which is not a good choice for anyone (except >> perhaps ostriches that want to bury their heads in the sand an ignore marginal >> DIMMs for as long as possible). > >Why isn't that a good choice?
It fails to use the capabilities of h/w an Linux to avoid a fatal error in the future. Corrected errors are (sometimes) a predictor of marginal/aging memory. Copying data out of a failing page while there are just corrected errors can avoid losing that whole page later.
A single error is plausibly a particle strike causing a bit flip. But a second error in the same page is a long shot (my desktop has 64G of memory, so 16 million pages ... that's an awful lot of other targets for a second particle strike).
>I'm sure there are error rates where this fits just fine.
Explain further. Apart from the "ostrich" case I'm not sure what they are.
>> So changing the threshold to "2" would be an improvement in at least >> being right for one vendor, instead of wrong for all. > >So I'm pretty sure that is not needed on AMD at all.
It's far more a property of DIMMs than of the CPU. Unless AMD are using some DECTED or better level of ECC for memory.
-Tony
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