Messages in this thread | | | Date | Thu, 21 Jun 2018 22:06:54 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses |
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On Tue, May 29, 2018 at 09:40:09AM -0700, Dave Hansen wrote: > Split-lock-detection is a new hardware feature that generates > alignment-check (#AC) faults to help detect when badly-aligned atomic > instructions might impact whole-system performance. These patches are > primarily targeted at application-level issues, but we can also detect > the same issues in the kernel.
Which is nice, Thomas and me spend quite a while searching for a perf event that could tell us about unaligned LOCK insns a few months back and could not find anything useful.
> There is a significant interaction > between this feature and firmware because firmware may or may not be > prepared for this feature to be enabled.
And allowing firmware to muddle through, instead of drawing a hard line in the sand means we'll be stuck with crap firmware for at least another decade :/
Just say no.
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