[Twisted-Python] a possible solution for ticket 5562
gelin yan
dynamicgl at gmail.com
Sat Oct 20 09:29:10 MDT 2012
Hi All
A few months ago, I reported a bug about IOCP. Last night I spent several
hours on its implementation and finally found out a possible solution for
that.
when sending some small chunks data continuously, the buffer will pile
them up and send to IOCP; however there is a SEND_LIMIT (128K) that means
only 128K will be handled. Now the problem is when we try to trigger the
next writing, IOCP will raise ERROR_IO_PENDING immediately and then
connection Lost.
So I got a idea: if the size of data is larger than SEND_LIMIT, we can
wait a little bit time for the next writing instead of do it immediately.
in twisted\internet\iocpreactor\abstract.py there is a method
def _cbWrite(self, rc, bytes, evt):
if self._handleWrite(rc, bytes, evt):
self.doWrite()
now I modified a bit,
def _cbWrite(self, rc, bytes, evt):
if self._handleWrite(rc, bytes, evt):
if len(evt.buff) < self.SEND_LIMIT:
self.doWrite()
else:
self.reactor.callLater(0.8,self.doWrite)
0.8 is a silly trial but I have no idea what is the right number for this
place. After this modification, previous problematic scripts can pass.
Maybe the better solution is to find a way to poll the complete port status
when read/write will be recovered from IO PENDING. Simply wait a little is
risky.
Regards
gelin yan
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