Can the distribution of a byte array be performance critical?

Question

On my small little file transfer website ( this one running .NET 4.5.1) I follow the article in the Microsoft Knowledge Base 812406 for sending previously downloaded files from a server to a browser.

Performing performance optimization, I was surprised to find that the line

var buffer = new byte[10000];

takes a significant percentage of the time (I use the Red Gate ANTI Performance Profiler ). The buffer is allocated only once for a full download / client.

My questions:

• Is it good to allocate a buffer this way and this size?
• Any alternatives when allocating a ~ 10k buffer?

Update 1:

Thanks to your comments, I saw that memory is also allocated inside the loop.

However, ANTS Profiler only notes that allocating outside the loop takes so much time, which I honestly don’t understand yet. I removed the (meaningless) selection inside the loop.

Update 2:

Having implemented the proposed BufferManager, and also reduced the buffer size from 10 to 4096 (just in case ...), my site has been working very smoothly since then.

Answer 1

Yes. In fact, WCF uses a “buffer manager” to prevent this problem .

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Answer 2

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// Gets the exact number of bytes read
length = iStream.Read(buffer, 0, 10000);

// Writes only 'length' bytes to the output
Response.OutputStream.Write(buffer, 0, length);

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: buffer= new Byte[10000]; while!

Answer 3

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