On 1 May, 04:31 pm, saurav.mohapa...@dimdim.com wrote: >Glyph, > >Thanks for the response.
No problem. Thanks for your clearly described inquiry :). >We're trying to proxy multiple VNC processes for a screen sharing >application. So though CPU load is low, the data being pushed out is >pretty high. We have around 16Kb of data being pushed out per second >per >client for a normal case. The test server is running on EC2, but we see >the degradation in the production deployment (on physical machines >running on a cogent fiber connection). I was thinking it might have >something to do with amount of data being written and number of >simultenous writes issued. Something to do with transport.write() When you do a transport.write, twisted puts the data into a buffer on your transport and marks it as ready to write some data. When you next get into epoll, epoll should wake up immediately, showing that lots of FDs are ready for writing, and Twisted will then immediately begin attempting to write all of the buffered data to those connections. All of those sockets are in non-blocking mode and so send will immediately return regardless of how much data can actually be put onto the wire. Therefore, in principle, if Twisted is not 100% busy on the CPU, then nothing *should* be causing it to deliver your data slower than it's coming in. Unless, of course, there's a bug, which is always possible. But this is a pretty simple bit of code and inspecting it in the course of this email I don't see many places for such a bug to hide; so in this case I'd probably start the bug hunt in the application. Or at least, by writing the simplest possible benchmark for Twisted itself, so that we can see the "raw" performance regardless of any application logic. >I can make a benchmarking application available to you, please mail me >off the list at saurav.mohapa...@dimdim.com I have done so. >Regards >Saurav _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
