Folks, I have spend past several miserable nights analyzing the performance of the new Coyote HTTP connector. I have discovered that HttpCommon code was horribly slow for larger request/response bodies, especially chunk-encoded, on my Linux box [1], whereas it seemed almost fine on a much slower WinXP laptop of my wife [2]. To cut a long and sad story short, after some investigations I found out that the culprit was NIO. The way I see it, NIO, as presently implemented in Sun's JREs for Linux, simply sucks. Actually blocking NIO appears more or less okay. The real problem is the NIO channel selector, which proves horribly expensive in terms of performance (we DO have to use a selector on the socket channel, because it is the only way (I know of) to implement socket timeout with NIO).
I have written a small test app to demonstrate the problem: http://svn.apache.org/repos/asf/jakarta/httpclient/trunk/http-common/src/test/tests/performance/NIOvsOldIO.java This is what I get on my Linux box ========================================= Old IO average time (ms): 1274 Blocking NIO average time (ms): 1364 NIO with Select average time (ms): 4981 ========================================= Bottom line: NIO may still be a better model for some special cases such as instant messaging where one can have thousands of mostly idle connections with fairly small and infrequent data packets. At the same time, I have come to a conclusion that NIO makes no sense of what so ever for synchronous HTTP (servlets, for instance), where large request/response entities need to be consumed/produced using InputStream/OutputStream interfaces, data tends to come in steady streams of chunks, and connections are relatively short-lived. I intent to remove all the NIO related class from HttpCommon and put them in the HttpAsynch module, where they may serve as a starting point for the asynchronous HTTP implementation. Please take a look at the test app and complain loudly if you think something is wrong. Otherwise I'll go ahead and get rid of NIO code in HttpCommon. Oleg === [1] Dell Dimension 8300, Pentium 4 3.00GHz, 512MB, Fedora Core 4, 2.6.11-1.1369_FC4smp [2] A pile of old trash running Windows XP Home SP2 (rather badly) --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
