[Mono-dev] Serialization performance + remoting

[pablosantosluac]

Rafael,

So, you basically mean changing the API from

MyType[] GetData()

to something like

byte[] GetData()

and perform the marshalling yourself?

Or maybe something like
MyArrayType GetData()

and then MyArrayType gets a customized serializer?

Thanks!

pablo


----- Original Message ----- 
From: "Rafael Teixeira" <monoman at gmail.com>
To: "Mirco Bauer" <meebey at meebey.net>
Cc: "pablosantosluac" <pablosantosluac at terra.es>; 
<mono-devel-list at lists.ximian.com>
Sent: Friday, August 03, 2007 4:21 PM
Subject: Re: [Mono-dev] Serialization performance + remoting


> Pablo,
>
> I should add that probably custom serialization should happen at the
> Array level, not each element, or you may end experiencing a similar
> problem with System.Runtime.Serialization.ObjectIDGenerator.
>
> If you know that all the array elements are different instances (no
> repeated references), it will be a huge gain, because that is
> something you don't have a way of letting the system provided
> serializer know, so it will keep trying to generate ids and check in
> the other end to point all references to a single deserialized
> instance.
>
> In those cases I normally serialize the whole array into a very
> compact and concise blob (forget the fields descriptors or send them
> just once) and deserialize at the other end. The added complexity is
> paid well in performance, for large sets of objects.
>
> In some cases I go even further and use compression/decompression of
> the blob, to achieve even less transport time, I just experiment a bit
> to find the right threshold (minimum size) where compression is
> beneficial (it is kind of a lookup table one have to construct, to
> adjust to the real speed of the connection).
>
> Hope it helps,
>
> On 8/3/07, Mirco Bauer <meebey at meebey.net> wrote:
>> On Thu, 2007-08-02 at 22:54 +0200, pablosantosluac wrote:
>> > Thanks Mirco,
>> >
>> > Well, all my objects are already marked as [Serializable] instead of
>> > extending the MarshalByRefObject.
>>
>> Ok, then you are passing the objects by value already.
>>
>> >
>> > So, you mean if I extend the class it will go worse?
>>
>> Yes :)
>> As it will only transfer a proxy object which will always make remoting
>> calls for each method or property usage.
>> So code like this is very bad:
>> for (int i = 0; i < 10; i++) {
>>         Console.WriteLine(myRemoteObject.SomeProperty);
>> }
>> that will cause 10 remoting calls...
>>
>> >
>> > The sample I'm using returns the 4700 objects in a single call (an 
>> > array is
>> > returned)
>> Hmmm ok, so you have performance problems with the binary serialization
>> itself, not with the remoting/call overhead.
>>
>> Then you might want to implement custom optimized binary serialization.
>> This can be done by implementing the serializable interface yourself. I
>> have not done this yet, but I will (for smuxi), as the built in binary
>> serialization of objects in MS .NET and Mono is pretty slow (actually
>> damn slow IMHO). The problem is that they are very generic
>> implementations to fit all cases, AFAIK.
>>
>> How to implement faster binary serialization check this out:
>> http://www.codeproject.com/csharp/FastSerialization.asp
>>
>> Maybe I will start a SmartBinarySerializer project :-P not sure...
>> As there is no free (as in MIT/X11, BSD, LGPL, whatever license)
>> implementation of an optimized binary serialization :(
>>
>> --
>> Regards,
>>
>> Mirco 'meebey' Bauer
>>
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>
>
> -- 
> Rafael "Monoman" Teixeira
> ---------------------------------------
> "I myself am made entirely of flaws, stitched together with good 
> intentions."
> Augusten Burroughs