serial ports, threads and windows

[Tom Brown]

Hey people,

I've written a python app that r/w eight serial ports to control eight devices
using eight threads. This all works very nicely in Linux. I even put a GUI on
it using PyQt4. Still works nicely.

Then I put the app on on a virtual Windows machine running inside of vmware on
the same Linux box. Vmware only lets me have four serial ports so I run the
app against four serial ports using four threads. The app did not respond
quick enough to data from the serial ports and eventually hung.

So, I tried one serial port and the app still did not respond quick enough to
the single serial port. It eventually hangs.

When the app hung, in each case, it was not hogging the cpu nor reading any
data off the serial ports. The task manager didn't show it was doing anything
at all.

When it runs on Windows, could it be:

1) Just struggling to run inside of VMware?

2) Using threads with Qt on Windows is a problem?

3) Threads in python on Windows is a problem?

Any ideas?

Thanks,
Tom

 

[placid]

When it runs on Windows, could it be:

1) Just struggling to run inside of VMware?

i have gut feeling that it could be that this is the problem.

 

[Grant Edwards]

When it runs on Windows, could it be:

1) Just struggling to run inside of VMware?

Could be.

Virtual machines are rather tricky things on broken
architectures that don't really permit true virtualization.

2) Using threads with Qt on Windows is a problem?

Doubt it.

3) Threads in python on Windows is a problem?

No.

 

[Pekka Niiranen]

Hey people,

I've written a python app that r/w eight serial ports to control eight devices
using eight threads. This all works very nicely in Linux. I even put a GUI on
it using PyQt4. Still works nicely.

Then I put the app on on a virtual Windows machine running inside of vmware on
the same Linux box. Vmware only lets me have four serial ports so I run the
app against four serial ports using four threads. The app did not respond
quick enough to data from the serial ports and eventually hung.

So, I tried one serial port and the app still did not respond quick enough to
the single serial port. It eventually hangs.

When the app hung, in each case, it was not hogging the cpu nor reading any
data off the serial ports. The task manager didn't show it was doing anything
at all.

When it runs on Windows, could it be:

1) Just struggling to run inside of VMware?

2) Using threads with Qt on Windows is a problem?

3) Threads in python on Windows is a problem?

Any ideas?

Thanks,
Tom

Hi,

I have been using wxpython myself with pyserial in Windows 2000/XP.
No problems. Below are (edited) code segments. The "self.jam" is
used for stopping serial port processing without stopping the thread.

-------- thread example starts --------------------

class T1Thread(Thread):
def __init__(self, inport):
Thread.__init__(self)
self._want_abort = 0
self.inprt = inport # COMx
self.inprt.flushInput()
self.run_count = 0
#
self.jam = false
#
self.start()

def run(self):
while self._want_abort == 0:
if not self.jam:
self.read_simulations()
sleep(1)

def abort(self):
self._want_abort = 1 # Stop from GUI


def read_simulations(self):
..blah..blah..
self.inprt.flushInput()
sleep(5)

-------- thread example ends --------------------

-------- Wxpython code starts --------------------

def OnRun(self, event):
if self.in_port != "No" and not self.T1worker:
self.T1worker = T1Thread(self.inprt)
if self.out_port != "No" and not self.T2worker:
self.T2worker = T2Thread(self.outprt)
if self.in2_port != "No" and not self.T3worker:
self.T3worker = T3Thread(self.in2prt)


def OnStop(self, event):
if self.T1worker:
self.T1worker.abort()
if self.T2worker:
self.T2worker.abort()
if self.T3worker:
self.T3worker.abort()
sleep(3)
self.T1worker= None
self.T2worker= None
self.T3worker= None
print "\nSTOPPED\n"

-------- Wxpython code ends --------------------

-pekka-