to be a little bit more precise, you will copy 64Mb the first time then 64Mb - 64kb the second time and so on
Jeff On Thu, Jan 10, 2013 at 12:11 PM, Emmanuel Lécharny <elecha...@gmail.com>wrote: > Le 1/10/13 10:56 AM, Jeff MAURY a écrit : > > The performance gain is not related to the nature of the buffer; I mean > > writing to an HeapBuffer vs writing to a DirectBuffer but related to > > writing the buffer to the socket: if you write an HeapBuffer to a socket, > > my guess is that it will be copied to a DirectBuffer before it gets > written > > to the socket which is not the case for a DirectBuffer > > This is exactly what happens. Internally, for each call to the > channel.write(HeapBuffer), there is a call to DirectBuffer.pu(HeapBuffer). > > You can imagine how costly this is when the HeapBuffer is 64 Mb big, and > we send only a fragment of it for each round... If the SendBufferSize is > 64Kb, in this case, you will just copy the 64Mb 1000 times. > > Good catch btw, Jeff ! > > > -- > Regards, > Cordialement, > Emmanuel Lécharny > www.iktek.com > > -- Jeff MAURY "Legacy code" often differs from its suggested alternative by actually working and scaling. - Bjarne Stroustrup http://www.jeffmaury.com http://riadiscuss.jeffmaury.com http://www.twitter.com/jeffmaury
