On 4/30/24 12:29 PM, Mina Almasry wrote:[...]
On Tue, Apr 30, 2024 at 6:46?AM Jens Axboe<axboe@xxxxxxxxx> wrote:
In general, attempting to hide overhead behind config options is alwaysThe history there is that this check adds 1 cycle regression to the
a losing proposition. It merely serves to say "look, if these things
aren't enabled, the overhead isn't there", while distros blindly enable
pretty much everything and then you're back where you started.
page_pool fast path benchmark. The regression last I measured is 8->9
cycles, so in % wise it's a quite significant 12.5% (more details in
the cover letter[1]). I doubt I can do much better than that to be
honest.
I'm all for cycle counting, and do it myself too, but is that even
measurable in anything that isn't a super targeted microbenchmark? Or
even in that?