[undertow-dev] Async sending of NIO objects thru a ServletOutputStream?

[Stuart Douglas]

1068            // Read from stream until buffer full or EOF
1069            _buffer.clear();
1070            while (_buffer.hasRemaining() && !_eof)
1071              _eof = (_in.read(_buffer)) <  0;

That pattern for reading from the stream only works for blocking IO. If 
you are using a non blocking channel this will basically wait in a busy 
loop till data becomes available.

Stuart

Jim Crossley wrote:
> Thanks, Jason. To me, the Jetty code looks like it's doing pretty much
> what Stuart told me to do. Can you tell me which part exactly assumes
> the blocking behavior so I can relay that to the Pedestal guys?
>
> On Tue, Sep 16, 2014 at 10:33 PM, Jason T. Greene <jgreene at redhat.com
> <mailto:jgreene at redhat.com>> wrote:
>
>
>
>     Sent from my iPhone
>
>     >  On Sep 16, 2014, at 8:19 PM, Jim Crossley <jim at crossleys.org
>     <mailto:jim at crossleys.org>> wrote:
>     >
>     >  Is this an async or a blocking transfer? The problem with
>     >  > ReadableByteChannel is that it can be a blocking channel, and as a
>     >  > result reading from it in the IO thread will result in crappy
>     >  > performance.
>     >
>     >  Because of the way they're using it (with Clojure's core.async
>     library)
>     >  I expect the transfer to be async, but I'll verify that with them.
>
>     I just looked at the Jetty impl, and the code assumes blocking
>     behavior with that method. Anything using it will be blocking reads
>     with non blocking writes.
>
>