[infinispan-dev] Double+ buffering during value marshalling

[Galder Zamarreño]

I don't really know tbh. More of a question for David.

To provide more background info, we have MarshalledValue in:
https://github.com/infinispan/infinispan/blob/master/core/src/main/java/org/infinispan/marshall/MarshalledValue.java

 It used to keep a byte[], but now we do some buffering in ExpandableMarshalledValueByteStream (https://github.com/infinispan/infinispan/blob/master/core/src/main/java/org/infinispan/io/ExpandableMarshalledValueByteStream.java) to be more efficient and avoid throwing away byte arrays, see https://issues.jboss.org/browse/ISPN-2032

What Sanne suggests is that we avoid double buffering in ExpandableMarshalledValueByteStream and SimpleDataOutput (RiverMarshaller).

There's a 1 to 1 mapping between the RiverMarshaller and the stream/buffer passed to Marshalling.createByteOutput(), so I think there could be an option where the stream passed is the actual buffer.

@Sanne, did you see any particular performace impact in the profiler? Or just noting it?

Cheers,

On Aug 13, 2012, at 6:22 PM, Manik Surtani wrote:

> Probably a question for David or Galder… but good detective work as always, Sanne.
> 
> On 11 Aug 2012, at 21:00, Sanne Grinovero <sanne at infinispan.org> wrote:
> 
>> While debugging around the Infinispan/JBMar integration I noticed that
>> Infinispan defines in-memory buffers wrapped as byte streams, and uses
>> JBoss Marshaller to write to these.
>> 
>> JBoss Marshaller also buffers writes, and flushes when needed or on
>> demand; I did already know of both, but just realized that these two
>> levels of buffering are both applied when serializing instances in a
>> org.infinispan.marshall.MarshalledValue; I guess we could do better
>> avoiding buffering and have JBMAR write straight away? It would also
>> mean less array resizing, as we are often able to allocate the right
>> size in one shot.
>> 
>> I gave a look into RiverMarshaller, and this didn't look like a simple
>> task as _byte[] buffer_ is the main element around which most of the
>> code revolves (in it's superclass SimpleDataOutput).
>> 
>> I'm wondering if SimpleDataOutput wouldn't be simpler by just writing
>> to a org.jboss.marshalling.ByteOutput (and have an optional buffering
>> implementation), or if Infinispan should use River in a different way.
>> 
>> Regards,
>> Sanne
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>> infinispan-dev at lists.jboss.org
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> 
> --
> Manik Surtani
> manik at jboss.org
> twitter.com/maniksurtani
> 
> Founder and Project Lead, Infinispan
> http://www.infinispan.org
> 
> Platform Architect, JBoss Data Grid
> http://red.ht/data-grid
> 

--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache