Re: [PATCH v9 net-next 2/7] net: add low latency socket poll

[Eliezer Tamir <eliezer.tamir@linux.intel.com>]

On 05/06/2013 18:39, Eric Dumazet wrote:
> On Wed, 2013-06-05 at 18:30 +0300, Eliezer Tamir wrote:
>> On 05/06/2013 18:21, Eric Dumazet wrote:

>>> It would also make sense to give end_time as a parameter, so that the
>>> polling() code could really give  a end_time for the whole duration of
>>> poll().
>>>
>>> (You then should test can_poll_ll(end_time) _before_ call to
>>> ndo_ll_poll())
>>
>> how would you handle a nonblocking operation in that case?
>> I guess if we have a socket option, then we don't need to handle none
>> blocking any diffrent, since the user specified exactly how much time to
>> waste polling. right?
>
> If the thread already spent 50us in the poll() system call, it for sure
> should not call any ndo_ll_poll(). This makes no more sense at this
> point.

what about a non-blocking read from a socket?
Right now we assume this means poll only once since the application will 
repeat as needed.

maybe add a "once" parameter that will cause sk_poll_ll() to ignore end 
time and only try once?