Volatile fields in the decoders

[Christian Migowski]

Hi Trustin,

did you make attempts to measure the penalty the decoders get from volatile?
The Netty-decoders don't do I/O therefor it is in most cases not
necessary to run them in different ExecutionHandler threads, but if
someone does, he _may_ get in trouble when the volatile is missing.
I didn't do any testing, but I have the feeling that removing volatile
will not improve performance measurably, but doing so potentially
dangers correct thread-safety of the decoders, i.e. i would keep it.

regards,
christian!


On Sat, Nov 7, 2009 at 6:24 PM, Frederic Bregier <fredbregier at free.fr> wrote:
>
> Hi Trustin,
>
> For me; I agree that most of the time, Codec are before ExecutionHandler.
> In fact, I have no real idea of other cases, except, if I search the extreme case, when one wants to "pipeline" two kinds of channels, for instance:
> "network-channel -> one codec -> execution handler -> business handler which writes on local-channel -> another codec -> another execution handler -> another business handler"
>
> I do this to pipeline several "business" stream into one network-channel.
> My guess is that probably there the codec for the local channel (the one in the middle named another codec) must be ok for multiple thread suport.
> Perhaps not all codec are necessary for that.
> Also I'm not completely sure that my example is a good one.. Just a guess more than an example...
> WDYT ?
>
> Frederic
>  ----- Original Message -----
>  From: Trustin Lee [via Netty Forums and Mailing Lists]
>  To: Frederic Bregier
>  Sent: Saturday, November 07, 2009 3:47 PM
>  Subject: Volatile fields in the decoders
>
>
>  Hi folks,
>
>  Currently, all decoders distributed with Netty define their state
>  fields as volatile, because I assumed that the decoders might be
>  placed after ExecutionHandler.  However, nobody seem to place them
>  after ExecutionHandler because decoding is a CPU bound task.
>  Therefore, I'd like to remove the volatile modifier if I did not miss
>  anything.  Please feel free to post your idea - it will be very
>  helpful regardless whether it's agreement or disagreement.
>
>  Thanks
>
>  — Trustin Lee, http://gleamynode.net/
>
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>  — Trustin Lee, http://gleamynode.net/
>
>
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