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Software remediation of the Meltdown and Spectre problems slows performance. If and when non-problematic processor models come to market, or microcode updates fix installed processors, will kernels and applications need flags or recompilation to avoid the slowdown due to software-based remediation?

ref: http://www.theregister.co.uk/2018/01/05/spectre_flaws_explained/

user15972
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    if the processors are fixed, then software remediation would be unnecessary – ravery Jan 08 '18 at 10:07
  • This seems like an issue for the Ubuntu Technical Board to discuss...when it's no longer hypothetical. Not a support question. – user535733 Jan 08 '18 at 12:34
  • I think we are putting the cart in front of the horse--Ubuntu hasn't releases a fix yet. Under kernel 4.14.12 (the Linux fix) I haven't seen performance impacted. – WinEunuuchs2Unix Jan 08 '18 at 13:43
  • You should read the release notes on this. Basically you add pti=off or nopti , either one, to your (grub) boot options - see https://askubuntu.com/questions/991874/how-to-disable-page-table-isolation-to-regain-performance-lost-due-to-intel-cpu/991879#991879 for a discussion and this option. See also https://fedoramagazine.org/kpti-new-kernel-feature-mitigate-meltdown/ – Panther Jan 08 '18 at 13:51
  • @Panther - nopti sets the worst case answer, and that is not so bad. I was asking if a future kernel will check for the problem itself and on its own, if it is safe, do nopti. – user15972 Jan 08 '18 at 19:46
  • @ user535733 - Technical Board - Go for it. – user15972 Jan 08 '18 at 19:46
  • @WinEunuuchs2Unix - Will wait. – user15972 Jan 08 '18 at 19:46

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