2023-11-20 14:38:43

by Peter Zijlstra

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Subject: [PATCH 0/2] x86/entry: Trade cycles

Hi,

Two little patches that trade a little performance. First patch optimizes
(although I couldn't get definite numbers showing it makes a difference) the
return to user path by avoiding some PTI specifics in the generic path.

Second patch then steals some of the won cycles by making a debug check
unconditional.

This came forth from a discussion with amluto who lamented we only had the
debug check conditional on DEBUG_ENTRY.



2023-11-21 15:26:44

by Thomas Gleixner

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Subject: Re: [PATCH 0/2] x86/entry: Trade cycles

On Mon, Nov 20 2023 at 15:33, Peter Zijlstra wrote:
> Two little patches that trade a little performance. First patch optimizes
> (although I couldn't get definite numbers showing it makes a difference) the
> return to user path by avoiding some PTI specifics in the generic path.
>
> Second patch then steals some of the won cycles by making a debug check
> unconditional.
>
> This came forth from a discussion with amluto who lamented we only had the
> debug check conditional on DEBUG_ENTRY.

Reviewed-by: Thomas Gleixner <[email protected]>