Hi, There is a problem with the fairness against writes no ? You can perhaps saturate the IoP with reading ? Julien
Le Thu, 30 Jul 2009 21:18:19 +0200,
Emmanuel Lecharny <elecha...@apache.org> a écrit :
> Hi guys,
>
> as I'm trying to document the IoProcessor main loop, I saw that the
> read( Session ) does read a buffer and then immediately push it to
> the chain, regardless there are more bytes in the socket :
>
> private void read(T session) {
> IoSessionConfig config = session.getConfig();
> IoBuffer buf = IoBuffer.allocate(config.getReadBufferSize());
>
> try {
> int readBytes = 0;
> int ret;
>
> try {
> ret = read(session, buf);
> if (ret > 0) {
> readBytes = ret;
> }
> }
> } finally {
> buf.flip();
> }
>
> if (readBytes > 0) {
> IoFilterChain filterChain = session.getFilterChain();
> filterChain.fireMessageReceived(buf);
>
>
> My question is : should we try to read as much data as we can,
> emptying the socket, then pushing the big buffer to the chain, or is
> it better to do as we do right now ?
>
> AFAICT, there are pros and cons for both cases.
>
> 1) Reading as much as we can
> cons :
> - we have to copy potentially a lot of buffers into a bigger one if
> we have, say many Kb of data available
> - we may suck a lot of memory to handle those buffers
> - we may have more than one message in the buffer
> pros :
> - less chain processing
> - probably less accumulation if we are using a cumulative protocol
> decoder
> - most certainly faster processing of messages
>
> 2) Reading a buffer and send it
> cons :
> - fragmentation of messages
> - many chain processing for potentially a single large message
> - many loops to process a complete message
> pros :
> - small buffers means less memory consumption
>
> I may be biased, but I tend to think that the first approach is
> probably better.
>
> thoughts ? as anyone able to conduct a load tests to compare both
> approaches if we implement the first approach ?
>
> Thanks !
>
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