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The Combined Impact Of Retpoline + KPTI On Ubuntu Linux

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  • #21
    Originally posted by Charlie68 View Post
    ...they also require a lot of work but it is not acceptable that these companies continue to sell defective cpus, the problem is them and they must solve it, otherwise they will continue to sell shit, as Linus T. rightly said.
    They can't just stop selling until they have it fixed because it will mean not selling a damn (either new or old) for a year or more, and all current stock (supposed to be sold over 2-5 years or maybe more) would become a net loss, even Intel would simply implode if that happens, and any of their customers will also take a heavy blow.

    Many industries are slow behemoths.

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    • #22
      Originally posted by starshipeleven View Post
      They can't just stop selling until they have it fixed because it will mean not selling a damn
      The point is they sold defective CPUs who need at minimum some performance degrading patches and did not tell there customers about it.

      If they told everyone "Hey there is a small security fuckup and future CPUs may take SOME FUCKING SIGNIFICANT PERFORMANCE LOSES", then it would have being OK to keep selling.

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      • #23
        Given Microsoft's comment on performance impact on older hardware it would be interesting to benchmark this on Haswell vs newer CPU generations.
        • "With Windows 10 on older silicon (2015-era PCs with Haswell or older CPU), some benchmarks show more significant slowdowns, and we expect that some users will notice a decrease in system performance."

        Ref: https://cloudblogs.microsoft.com/mic...ndows-systems/

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        • #24
          Originally posted by cl333r View Post
          Will the upcoming Intel/AMD CPUs come with these issues fixed in silicon or is it possible at all?
          amd cpus have no meltdown bug

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          • #25
            Originally posted by bridgman View Post

            ??? More like driving a non-fiddled vehicle from another mfg but patching in the performance-impacting VW changes even though they are not needed.

            Actually given the specifics of the emissions "fix" the analogy might be beyond saving
            Not necessarily, Spectre affects cross board CPU manufacturers where as Meltdown is Intel's problem of it's own making in the pursuit of performance over security. Depending on the country you live in the specifics of the fix for VW range from software to a lot more draconian requiring the fitting of extra parts:

            https://blog.caranddriver.com/everyt...sions-scandal/

            Perhaps it's time to bring back the abacus and walking



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            • #26
              Originally posted by Kraut View Post
              The point is they sold defective CPUs who need at minimum some performance degrading patches and did not tell there customers about it.
              it happens all the time. google for "errata"

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              • #27
                Originally posted by Michael View Post

                Was benchmarked yesterday with Retpoline on Intel and AMD: https://www.phoronix.com/scan.php?pa...nchmarks&num=1


                AMD said that their cpus are almost totally immune to variant 2 of spectre (the one with the worse performance penalties). From your benchmark results seems that the fix for variant 2 is still enabled for AMD cpus: can you please benchmark AMD cpus with just the "variant 1" fix in order to see what's the performance penalty?
                ## VGA ##
                AMD: X1950XTX, HD3870, HD5870
                Intel: GMA45, HD3000 (Core i5 2500K)

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                • #28
                  Originally posted by Kraut View Post
                  The point is they sold defective CPUs who need at minimum some performance degrading patches and did not tell there customers about it.

                  If they told everyone "Hey there is a small security fuckup and future CPUs may take SOME FUCKING SIGNIFICANT PERFORMANCE LOSES", then it would have being OK to keep selling.
                  Heh, their statements are in line with what other companies did.

                  If you mean they kept Meltdown and Spectre secret for decades, then yeah, if they did that instead of fixing it they are a bag of disks.

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                  • #29
                    Originally posted by Slartifartblast View Post
                    Not necessarily, Spectre affects cross board CPU manufacturers where as Meltdown is Intel's problem of it's own making in the pursuit of performance over security.
                    That was my point as well - KPTI is "the fix" for Meltdown, not Spectre, which is why the poster you responded to said that testing AMD with KPTI was like testing a car with the handbrake on. I still don't understand why you think testing AMD with KPTI is like testing a VW with a fix for the emissions hack.
                    Test signature

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                    • #30
                      Originally posted by darkbasic View Post
                      AMD said that their cpus are almost totally immune to variant 2 of spectre (the one with the worse performance penalties). From your benchmark results seems that the fix for variant 2 is still enabled for AMD cpus: can you please benchmark AMD cpus with just the "variant 1" fix in order to see what's the performance penalty?
                      And bench against Intel with all fixes applied

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