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albright
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PostPosted: Thu Nov 22, 2018 12:15 pm    Post subject: Advice on STIBP? Reply with quote

According to various reports, spectre like attack mitigations have
a large negative impact on performance across a wide range
of cases (see e.g. https://www.phoronix.com/scan.php?page=news_item&px=Linux-Torvalds-STIBP-Comment).

I hear that the offending, so to speak, code is back ported to 4.19.2.

So my questions are

1. is there a way to avoid the STIBP code and run 4.19.2 and beyond?
2. how much actual performance hit is there on typical gentoo system?

Any advice appreciated?

(maybe this topic should be in "other things ..." BTW)
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truekaiser
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PostPosted: Thu Nov 22, 2018 9:21 pm    Post subject: Reply with quote

linus has spoken up and said the default should be opt in due to the catastrophic performance impact.
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Naib
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PostPosted: Thu Nov 22, 2018 10:20 pm    Post subject: Reply with quote

newer kernel updates has lessened the impact https://www.phoronix.com/scan.php?page=news_item&px=Linux-Stable-Dropping-STIBP
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albright
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PostPosted: Sat Nov 24, 2018 2:11 pm    Post subject: Reply with quote

in 4.19.4:

Quote:
Greg Kroah-Hartman (2):
Revert "x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation"
Linux 4.19.4


from https://lwn.net/Articles/772853/
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