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well as it turned out one worker thread was not enough. So whenever a
message arrives it is now put in its own tasklet after which the worker
can wait for new input again. The tasklet will run to its end and will
be cleaned up later.<br>
<br>
That solved my problems that as it turned out was that the worker
thread received a new request before the old one has finished, yet it
needed to process the new request in order to finish the first...<br>
<br>
Oh the joys of parallel programming....<br>
<br>
<br>
Paul Sijben wrote:
<blockquote cite="mid45E7CDD7.6050509@eemvalley.com" type="cite">
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
Andres, Richard,<br>
<br>
thanks for the input! <br>
Indeed I have a multi-threaded UDP server going. I was running out of
regular threads so I am porting it to stackless.<br>
<br>
What I learned over the past days is that unless you have a loop
constantly doing a blocking(!) recvfrom on a socket you will lose the
UDP packets that arrive when you are not actively listening. I sorted
all of that out now by creating a couple of threads, so I have a thread
that may block all it likes on the socket and a worker thread that
actually holds the tasklets to handle the incoming messages.<br>
<br>
My current problem is a logic problem. Halfway through my test scenario
the server calls itself. At some point a return on one of those calls
does not seem to find a tasklet waiting for it.<br>
<br>
It is one of those painful things when you have something massively
parallel....<br>
<br>
In the process I made the attached drop-in modules to replace the
regular queue and threading as part of a quick porting action. (i.e.
import muQueue as queue). This might be of use to people who have a
less complex problem on their hands ;-)<br>
<br>
Paul<br>
<br>
Andrew Francis wrote:
<blockquote cite="mid134822.24156.qm@web34215.mail.mud.yahoo.com"
type="cite">
<pre wrap="">Message: 6
Date: Wed, 28 Feb 2007 18:26:53 +0000
From: "Richard Tew" <a class="moz-txt-link-rfc2396E"
href="mailto:richard.m.tew@gmail.com"><richard.m.tew@gmail.com></a>
Subject: Re: [Stackless] stackless socket, curiouser
and curiouser
</pre>
<blockquote type="cite">
<pre wrap="">To: "Paul Sijben" <a class="moz-txt-link-rfc2396E"
href="mailto:sijben@eemvalley.com"><sijben@eemvalley.com></a>
</pre>
</blockquote>
<pre wrap=""><!---->Cc: <a class="moz-txt-link-abbreviated"
href="mailto:stackless@stackless.com">stackless@stackless.com</a>
Message-ID:
</pre>
<blockquote type="cite">
<pre wrap="">If it is more important to you to just get things
done, you might be better off to look at using a
networking framework which is known to
work with Stackless. I do not have any personal
knowledge of any which do so without some other form
of shenanigans involved. However there are some
people on the list with experience mixing Stackless
with Twisted who might wish to help out if you choose
to go that direction.
</pre>
</blockquote>
<pre wrap=""><!---->
Paul, I am not sure what you are trying to do but it
seems to involve setting up a UDP server. I feel
packages like asyncore simply require too much work to
do even for the simplest of programmes.
Here is a quick example I wrote based on the Twisted
Echo server example at
<a class="moz-txt-link-freetext"
href="http://twistedmatrix.com/projects/core/documentation/howto/udp.html">http://twistedmatrix.com/projects/core/documentation/howto/udp.html</a>
The server listens at port 9999. When a connection
comes in, a tasklet prints out connection information.
I feel the solution is relatively easy to follow.
~~~~
#!/usr/bin/env python
"""
UDPServer.py
Andrew Francis
March 1st, 2007
Simple example of a UDP server using Twisted and
Stackless
Based on the Echo server example at
<a class="moz-txt-link-freetext"
href="http://twistedmatrix.com/projects/core/documentation/howto/udp.html">http://twistedmatrix.com/projects/core/documentation/howto/udp.html</a>
<song>Rebellion - Arcade Fire</song>
"""
import stackless
from twisted.internet.protocol import DatagramProtocol
from twisted.internet import reactor
class Echo(DatagramProtocol):
def __init__(self, requestChannel):
self.channel = requestChannel
return
def datagramReceived(self, data, (host, port)):
self.channel.send((data, host, port))
self.transport.write(data, (host, port))
class EchoServer(object):
def execute(self, port, requestChannel):
reactor.listenUDP(port, Echo(requestChannel))
reactor.run()
class EchoTasklet(object):
def __init__(self, name, channel):
self.channel = channel
return
def execute(self):
while (1):
data, host, port = self.channel.receive()
print "received %r from %s:%d" % (data,
host, port)
stackless.schedule()
if __name__ == "__main__":
from twisted.internet import reactor
"""
for simplicity - share the channel
"""
requestChannel = stackless.channel()
listener = EchoTasklet(requestChannel)
server = EchoServer()
stackless.tasklet(listener.execute)()
stackless.tasklet(server.execute)(9999,
requestChannel)
while (stackless.getruncount() > 1):
stackless.schedule()
Cheers,
Andrew
____________________________________________________________________________________
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Paul Sijben tel: +31334566488
Eemvalley Technology fax: +31334557523
the Netherlands <a class="moz-txt-link-freetext"
href="http://eemvalley.com">http://eemvalley.com</a>
</pre>
<pre wrap="">
<hr size="4" width="90%">
import channelWithReceiveTimeout
from MercuryFundamentals import debug
import time
class Empty(Exception):
def __init__(self):
Exception.__init__(self)
class Queue:
def __init__(self,len=None):
self.__queue=channelWithReceiveTimeout.TimeLimitedReceiveChannel()
debug("__init__%s"%self.__queue)
def put(self,val):
debug("putting %s in %s"%(val,self.__queue))
self.__queue.send((time.time(),val))
def get(self,number=None,timeout=None):
debug("timeout %s getting from %s"%(timeout,self.__queue))
(t,val)= self.__queue.receive(timeout)
debug("received from %s data with %s delay"%(self.__queue,(time.time()-t)))
print val
return val
</pre>
<pre wrap="">
<hr size="4" width="90%">
import stackless
class Thread:
def __init__(self):
self.__running=False
print "tasklet initing.....",
self.__task=stackless.tasklet(self.run)
print self.__task
def start(self):
print "tasklet starting....", self
print "...2...."
self.__task.setup()
print "...3...."
if not self.__running:
print "...4...."
self.__task.insert()
print "...5...."
self.__running=True
def join(self):
print "------------------- killing tasklet",self
try:
self.__task.kill()
except:
print "############## got exception killing tasklet,%s, ignoring"%self
pass
</pre>
<pre wrap="">
<hr size="4" width="90%">
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Paul Sijben tel: +31334566488
Eemvalley Technology fax: +31334557523
the Netherlands <a class="moz-txt-link-freetext" href="http://eemvalley.com">http://eemvalley.com</a>
</pre>
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