Re: [RFC] x86_64: A real proposal for iret-less return to kernel

From: Andi Kleen
Date: Wed May 21 2014 - 18:25:48 EST



Seems like a lot of effort and risk to essentially only optimize in kernel
interrupt handlers.

AFAIK the most interesting cases (like user page faults) are not
affected at all. Usually most workloads don't spend all that much time
in the kernel, so it won't help most interrupts.

I suspect the only case that's really interesting here is interrupting
idle. Maybe it would be possible to do some fast path in this case only.

However idle currently has so much overhead that I suspect that there
are lower hanging fruit elsewhere.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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