async poll

[John Myers]

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Davide Libenzi wrote:

>Maybe my understanding of AIO on Linux is limited but how would you do
>async accept/connect ? Will you be using std poll/select for that, and
>then you'll switch to AIO for read/write requests ?
>
If a connection is likely to be idle, one would want to use an async 
read poll instead of an async read in order to avoid having to allocate 
input buffers to idle connections.  (What one really wants is a variant 
of async read that allocates an input buffer to an fd at completion 
time, not submission time).

Sometimes one wants to use a library which only has a nonblocking 
interface, so when the library says WOULDBLOCK you have to do an async 
write poll.

Sometimes one wants to use a kernel interface (e.g. sendfile) that does 
not yet have an async equivalent.  Accept/connect are in this 
class--there should be nothing to prevent us from creating async 
versions of accept/connect.

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