Ultra low latency in cluster application

[David Alves]

Hi Frederic
 Yes I've tryed installing same jdk (sun, 1.6, 32 bit) on both 1 and 2
machines and the problem persists.
 I serialize my messages (POJOs) through DataInput/DataOutput (I'm using
Writable from hadoop which delegates the serialization algo to the POJO
itself and is done by calling  writeInt(), writeLong() etc). In all comm
protocols I've tryed this has been the faster approach.
 My connections are persistent (keep aline is set to true) the channel is
created once on client connection and then all the messages are sent through
that channel.
 The only way I can prevent the problem is by using plain old blocking
Sockets, there the latency is minimal, but the throughput also plummets 10
fold (dropping from 40.000 to 5.000 on my mac). What I find curious is that
Oio in netty is supposed to be built over the old sockets right? If i use
Oio the latency still increases...

Regards
David



On Wed, Feb 25, 2009 at 4:28 PM, Frederic Bregier <fredbregier at free.fr>wrote:

>
> Hi David,
> So it is probably not related to a particular JDK.
> Do you have try to use (to be sure) same JDK on both side
> (or at least same big level like 1.6 and also same type of xxbit - 32 xor
> 64
> its -) ?
> I did not have any problem with Sun JDK until now (just to let you know).
> If you use POJO between clients and server, could it be related (32 vs
> 64bit) ?
>
> Another idea:
> Do you always opened and closed the channel for every message
> or stay opened as long as you can ?
> But I'm agree, even like that, it should not have a 100s of latency.
>
> At this point, I've got no new idea...
>
> Regards,
> Frederic
>
>
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