Re: [PATCH 0/2] task_put batching

[Jens Axboe <axboe@kernel.dk>]

On 7/18/20 2:32 AM, Pavel Begunkov wrote:
> For my a bit exaggerated test case perf continues to show high CPU
> cosumption by io_dismantle(), and so calling it io_iopoll_complete().
> Even though the patch doesn't yield throughput increase for my setup,
> probably because the effect is hidden behind polling, but it definitely
> improves relative percentage. And the difference should only grow with
> increasing number of CPUs. Another reason to have this is that atomics
> may affect other parallel tasks (e.g. which doesn't use io_uring)
> 
> before:
> io_iopoll_complete: 5.29%
> io_dismantle_req:   2.16%
> 
> after:
> io_iopoll_complete: 3.39%
> io_dismantle_req:   0.465%

Still not seeing a win here, but it's clean and it _should_ work. For
some reason I end up getting the offset in task ref put growing the
fput_many(). Which doesn't (on the surface) make a lot of sense, but
may just mean that we have some weird side effects.

I have applied it, thanks.

-- 
Jens Axboe