[Twisted-Python] does setTcpNoDelay() not work?

Gabriel Rossetti gabriel.rossetti at arimaz.com
Mon Aug 11 14:18:43 EDT 2008

Jean-Paul Calderone wrote:
> On Mon, 11 Aug 2008 19:13:56 +0200, Gabriel Rossetti 
> <gabriel.rossetti at arimaz.com> wrote:
>> Gabriel Rossetti wrote:
>>> Hello,
>>> I'm needing to send small packets to update a progress bar. My 
>>> update msgs were all being sent in big packets, so I tried setting 
>>> setTcpNoDelay() in connectionMade() but it doesn't change anything, 
>>> is it broken?
>>> Thank you,
>>> Gabriel
>> I an using code that I wrote using threads.deferToThread(), I 
>> wondered if it was blocking the reactor maybe, so I tried just using 
>> a plain deferToThread() call. Here's the code (without all the 
>> protocol stuff, it's executed when data come in.
>>    def loop(self):
>>        import time
>>        m = utils.createMessage("toto", "hello")
>>        while(True):
>>            print "Sending %s" % m.toXml()
>>            self.sendMessage(m)
>>            print "Sent!"
>>            time.sleep(2)
>> threads.deferToThread(self.loop)
>> the TCP no delay option is turned on like I said before, the weird 
>> thing is that I have the same thing, all my msgs get sent in big 
>> blocks. Either the TCP no delay doesn't work, or the reactor is 
>> getting tied up. I don' t get it since I'm running the blocking code 
>> in a thread, the reactor should have nothing to do.
> Since you didn't include the definition of `sendMessage´, it's hard to 
> say
> what's really going on here.  However, my guess is that you're calling 
> the
> transport.write method in a non-reactor thread, which is not allowed.
> If this isn't the case, including a full, minimal example in your next
> message would be a good idea. :)
> Jean-Paul
Yes, self.sendMessage() calls transport.write. So there's no way of 
sending msgs from a non-reactor thread, even if it has a reference to 
the protocol?


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