On Thu, May 18, 2023 at 02:17:48PM -0700, Stefan Roesch wrote:
> This adds the napi busy polling support in io_uring.c. It adds a new
> napi_list to the io_ring_ctx structure. This list contains the list of
> napi_id's that are currently enabled for busy polling. The list is
> synchronized by the new napi_lock spin lock. The current default napi
> busy polling time is stored in napi_busy_poll_to. If napi busy polling
> is not enabled, the value is 0.
>
> In addition there is also a hash table. The hash table store the napi
> id ond the pointer to the above list nodes. The hash table is used to
nit: is 'ond' correct here?
> speed up the lookup to the list elements. The hash table is synchronized
> with rcu.
>
> The NAPI_TIMEOUT is stored as a timeout to make sure that the time a
> napi entry is stored in the napi list is limited.
>
> The busy poll timeout is also stored as part of the io_wait_queue. This
> is necessary as for sq polling the poll interval needs to be adjusted
> and the napi callback allows only to pass in one value.
>
> This has been tested with two simple programs from the liburing library
> repository: the napi client and the napi server program. The client
> sends a request, which has a timestamp in its payload and the server
> replies with the same payload. The client calculates the roundtrip time
nit: checkpatch.pl --codespell says:
:636: WARNING: 'calcualte' may be misspelled - perhaps 'calculate'?
and stores it to calcualte the results.
^^^^^^^^^
...
