tomaswolf commented on issue #293: URL: https://github.com/apache/mina-sshd/issues/293#issuecomment-1374645896
The problem in SFTP is caused by excessively jumping back and forth in the file on the server side. It manifests only with NIO2 and MINA but not with Netty because timing is different and the files end up being read more or less sequentially, or the backwards jumps are within some OS buffer size. With NIO2 and MINA, more initial read requests appear to be handled before a backwards jump occurs, which then leads to more and larger backwards jumps if one keeps issuing asynchronous requests. I did not analyze why the problem did not occur on Windows or locally on OS X; perhaps these OSes handle this better than Linux, or the request timings and their handling are more like in the Netty/Linux case. I still have no idea why the problem occurs from a particular GitHub CI build on. Perhaps something in the Linux container used to run the tests changed. In any case I have not found any particular commit from which on the performance would have dropped markedly on Linux; the problem was apparent in all runs in my local CentOS 7 VM, no matter how far back I went. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
