[PATCH 1/2] locking/lockref: Use try_cmpxchg64 in CMPXCHG_LOOP macro
Linus Torvalds
torvalds at linux-foundation.org
Fri May 27 02:52:04 AEST 2022
On Thu, May 26, 2022 at 5:15 AM Michael Ellerman <mpe at ellerman.id.au> wrote:
>
> Do you know of a benchmark that shows it up? I tried a few things but
> couldn't get lockref_get() to count for more than 1-2%.
Heh. 1% for a small instruction sequence that is only handful of
instructions and is used in just a couple of places counts as "very
hot" for me.
I assume you did the natural thing: threaded pathname lookup (with
paths being of the longer variety to not be dominated by system call
etc costs).
Linus
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