[HN Gopher] CPU Bugs (2018)
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       CPU Bugs (2018)
        
       Author : for_xyz
       Score  : 24 points
       Date   : 2021-05-22 09:26 UTC (1 days ago)
        
 (HTM) web link (danluu.com)
 (TXT) w3m dump (danluu.com)
        
       | userbinator wrote:
       | It's funny to hear that the bug increases are an effect of Intel
       | trying to compete with ARM SoCs in mobile devices, because the
       | errata those have are _much_ worse --- and indeed a lot of
       | embedded stuff is like that because the general line of thought
       | there is that bugs are worked around in software and there 's
       | little expectation of being able to run existing code flawlessly,
       | unlike with a PC.
        
         | bombcar wrote:
         | Nowadays there's hardly a device that can't easily be updated
         | after shipment - so the cost and effort required to make a
         | perfect error-free CPU is not as incentivezed.
        
           | formerly_proven wrote:
           | Are there ARM CPUs that have upgradeable microcode?
        
           | jeffbee wrote:
           | The updates are often fatal, though. These include things
           | like the Opteron "Barcelona" TLB bug and the first-generation
           | EPYC "Naples" frequency scaling bug. The fix for the former
           | knocked 20% off the performance of that generation of parts,
           | and the fix for the latter meant that you had to run at the
           | base clock frequency at all times, getting neither turbo
           | boosts nor power savings. If you apply all of the speculative
           | execution workarounds to an older Intel part like Xeon E5 v3
           | you will lose something like a quarter of the performance you
           | paid for originally.
        
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       (page generated 2021-05-23 23:00 UTC)