[PyKDE] high event volumes causing seg faults
Phil Thompson
phil at riverbankcomputing.co.uk
Wed Dec 31 11:19:00 GMT 2003
On Wednesday 31 December 2003 12:39 am, Patrick Stinson wrote:
> out of curiosity: is that a general suggestion about the snapshots or one
> related to my problem?
Both.
Phil
> On Tuesday 30 December 2003 03:19, Phil Thompson wrote:
> > Version numbers?
> >
> > If you are not already doing so I'd suggest using the latest SIP v4 and
> > PyQt snapshots.
> >
> > Phil
> >
> > On Monday 29 December 2003 7:47 am, Patrick Stinson wrote:
> > > I'm using alsa's rawmidi interface to read midi messages from hardware,
> > > then pumping them to my qt application code. The problem thus far has
> > > been dealing with the higher (~50-100/sec) volumes of messages received
> > > in a dedicated thread, and integrating them safely into the main qt
> > > event thread.
> > >
> > > My midi class has a blocking read method that produces messages. a
> > > python thread is created to call it, and messages are put into a
> > > Queue.Queue object. Another python thread reads from the queue and uses
> > > QApplication.postEvent to get the message into the qt thread. All is
> > > fine until I call a method like 'QSlider.setValue' that changes the way
> > > a widget looks from my overridden QWidget.event() method. I've tried
> > > setting a single-millisecond timer to generate events in place of the
> > > midi object, and of course, everything works fine. Why is it that the
> > > slider dies when the 'events', however proxied, originate in the midi
> > > thread?
> > >
> > > Sometimes I'm getting negative ref counts; what could be left over or
> > > deleted so fast that python/qt couldn't keep up?
> > >
> > >
> > > here is the simple result from an attempt at a
> > > [midi thread: Queue.put()] ->
> > > [dispatch thread: Queue.get(), QApplication.postEvent()] ->
> > > [qt thread: event(),QEvent.data()]
> > >
> > >
> > > bash-2.05b$ pksampler
> > > WAD Enabled
> > > pkaudio: found 4 devices, but only using 1.
> > > pkaudio: ->> Found device: hw:PCI,0
> > > pkaudio: outputs: 2
> > > pkaudio: inputs: 2
> > > pkaudio: [[loaded device 1]]
> > > pkaudio: ->> Found device: hw:Extigy,0
> > > pkaudio: outputs: 6
> > > pkaudio: inputs: 2
> > > pkaudio: sample rates: 48000
> > > pkaudio: ->> Found device: hw:Extigy,2
> > > pkaudio: outputs: 2
> > > pkaudio: inputs: 0
> > > pkaudio: sample rates: 48000
> > > PKSampler: driver buffer size: 2048
> > > PKSampler: driver sample rate: 44100
> > > PKSampler: All daemons up and running
> > > WAD: Collecting debugging information...
> > > WAD: Segmentation fault.
> > > #12 0x40238247 in __clone()
> > > #11 0x40030d40 in pthread_start_thread()
> > > #10 0x080ee9bd in t_bootstrap()
> > > #9 0x080c2da9 in PyEval_CallObjectWithKeywords()
> > > #8 0x0805c3fe in PyObject_Call()
> > > #7 0x080642d3 in instancemethod_call()
> > > #6 0x0805c3fe in PyObject_Call()
> > > #5 0x0810d125 in function_call()
> > > #4 0x080c162f in PyEval_EvalCodeEx()
> > > #3 0x080bf82f in eval_frame()
> > > #2 0x080c3119 in call_function()
> > > #1 0x0810d8d6 in PyCFunction_Call()
> > > #0 0x417f58b1 in _Z26sipDo_QCustomEvent_setDataP7_objectS0_()
> > >
> > >
> > > --------------------------------------
> > >
> > >
> > > I've had several horrendous stack traces, but I think the following one
> > > best suits the extent of my problem...
> > >
> > > PKSampler: All daemons up and running
> > > WAD: Collecting debugging information...
> > > SegFault: [ C stack trace ]
> > >
> > > #50 0x080b9ef4 in PyEval_EvalCode()
> > > #49 0x080c162f in PyEval_EvalCodeEx()
> > > #48 0x080bf82f in eval_frame()
> > > #47 0x080c3119 in call_function()
> > > #46 0x0810d8d6 in PyCFunction_Call()
> > > #45 0x418de03b in _Z28sipDo_QApplication_exec_loopP7_objectS0_()
> > > #44 0x40563b11 in _ZN12QApplication4execEv()
> > > #43 0x40576928 in _ZN10QEventLoop4execEv()
> > > #42 0x40576a86 in _ZN10QEventLoop9enterLoopEv()
> > > #41 0x4050fea4 in _ZN10QEventLoop13processEventsEj()
> > > #40 0x4055301d in _ZN10QEventLoop14activateTimersEv()
> > > #39 0x418db9fb in _ZN15sipQApplication6notifyEP7QObjectP6QEvent()
> > > #38 0x40562cb5 in _ZN12QApplication6notifyEP7QObjectP6QEvent()
> > > #37 0x405638c5 in
> > > _ZN12QApplication14internalNotifyEP7QObjectP6QEvent() #36 0x41598b6f
> > > in _ZN9sipQTimer5eventEP6QEvent()
> > > #35 0x405df932 in _ZN6QTimer5eventEP6QEvent()
> > > #34 0x408da8eb in _ZN6QTimer7timeoutEv()
> > > #33 0x405be454 in _ZN7QObject15activate_signalEi()
> > > #32 0x405be620 in
> > > _ZN7QObject15activate_signalEP15QConnectionListP8QUObject() #31
> > > 0x41907334 in _ZN10sipProxyqt9qt_invokeEiP8QUObject()
> > > #30 0x41523175 in _ZN10sipProxyqt9proxySlotEv()
> > > #29 0x40019fdf in _Z13sipEmitToSlotP7sipSlotP7_object()
> > > #28 0x080c2da9 in PyEval_CallObjectWithKeywords()
> > > #27 0x0805c3fe in PyObject_Call()
> > > #26 0x080642d3 in instancemethod_call()
> > > #25 0x0805c3fe in PyObject_Call()
> > > #24 0x0810d125 in function_call()
> > > #23 0x080c162f in PyEval_EvalCodeEx()
> > > #22 0x080bf82f in eval_frame()
> > > #21 0x080c325b in call_function()
> > > #20 0x080c3463 in fast_function()
> > > #19 0x080bf82f in eval_frame()
> > > #18 0x080c325b in call_function()
> > > #17 0x080c3463 in fast_function()
> > > #16 0x080bf82f in eval_frame()
> > > #15 0x080c3119 in call_function()
> > > #14 0x0810d8d6 in PyCFunction_Call()
> > > #13 0x41b4223d in _Z23sipDo_PK_Effect_ControlP7_objectS0_()
> > > #12 0x40020157 in sipMapCppToSelf()
> > > #11 0x4001b713 in sipNewCppToSelf()
> > > #10 0x0805ea92 in PyInstance_New()
> > > #9 0x080c2da9 in PyEval_CallObjectWithKeywords()
> > > #8 0x0805c3fe in PyObject_Call()
> > > #7 0x080642d3 in instancemethod_call()
> > > #6 0x0805c3fe in PyObject_Call()
> > > #5 0x0810d125 in function_call()
> > > #4 0x080c16a8 in PyEval_EvalCodeEx()
> > > #3 0x08082a95 in _Py_Dealloc()
> > > #2 0x0810a7c6 in frame_dealloc()
> > > #1 0x08082a8a in _Py_Dealloc()
> > > #0 0x08082a1e in _Py_ForgetReference()
> > >
> > > pkaudio: buffer thread exiting.
> > > pkaudio: engine thread exiting.
> > > PKSampler: All daemons stopped cleanly.
> > > [40724 refs]
> > > Fatal Python error: Objects/frameobject.c:403 object at 0x81ff8a4 has
> > > negative ref count -1
> > > WAD: Collecting debugging information...
> > > WAD: Abort.
> > > #14 0x08054ca1 in ?()
> > > #13 0x4017390c in __libc_start_main()
> > > #12 0x08054d5a in main()
> > > #11 0x08055638 in Py_Main()
> > > #10 0x080e5b61 in Py_Finalize()
> > > #9 0x080e45ca in PyInterpreterState_Clear()
> > > #8 0x080e4a9c in PyThreadState_Clear()
> > > #7 0x08082a95 in _Py_Dealloc()
> > > #6 0x0810a7b6 in frame_dealloc()
> > > #5 0x0807ec70 in _Py_NegativeRefcount()
> > > #4 0x080e838b in Py_AtExit()
> > > #3 0x401885fb in __GI_abort()
> > > #2 0x40187094 in __GI_raise()
> > > #1 0x4003386b in __pthread_raise()
> > > #0 0x401872e1 in __kill()
> > >
> > >
> > >
> > > _______________________________________________
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> > > http://mats.imk.fraunhofer.de/mailman/listinfo/pykde
> >
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