Re:Linux page table isolation is not needed on AMD processors
by freeone3000 on Tuesday January 02, 2018 @02:31PM
(#16054699)
Why would this cause you to diversify? Long-term negative effects of a monoculture are not evenly distributed to purchasers. In fact, if you ran both AMD and Intel CPUs, you'd see application performance differences solely based on processor architecture. This makes application deployment planning way harder. At any given time, there's one CPU that should be purchased, and artificially introducing two "so they don't fail the same way" is bad, specifically because they won't fail the same way.
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Re:Linux page table isolation is not needed on AMD processors
by myrandomcomment on Wednesday January 03, 2018 @02:21AM
(#16059196)
It depends. There was a reason back in the day that if you were a telco you have phone switches from from 2 providers,ie a DMSxxx and ESSxxx. Another example would be how the big providers got screwed by the in ability of Cisco to get their GSR working right without a few forklift upgrades (really they were moved with a forklift). This opened the path for Juniper. For a long time the telcos moved to have one router from each so a nasty bug in one would not take them down. In a properly tooled setup you should be able to account for the load characteristics between AMD and Intel. Having 2 is safer then one.
Google is pushing both PowerCPU development as well as ARM. They seem to be able to sort for this just fine. You can write tools to sort the differences. You cannot write tools to fix major HW issue.
Anyway my 2 cents based on experience and history for whatever the comments of a random person on the intertubes is worth.
Re:Linux page table isolation is not needed on AMD processors
by phamilton on Wednesday January 03, 2018 @01:53AM
(#16059089)
Imagine you are AWS. You have a range of instance types with various performance characteristics. Having customers move from c5s to c4s is much better than customers moving from AWS to GCE.