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Re: [Matplotlib-users] a memory leak in matplotlib plot embedded inwxpython
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From: Barraclough, D. \(e. 414\) <dj...@qv...> - 2012-09-12 16:37:04
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Happiness - Upgrading numpy to v 1.6.2 - I had been using 1.6.0b - seems to have fixed things - my app's memory usage is now flat. Dominic ________________________________ From: Barraclough, Dominic (ext. 414) [mailto:dj...@qv...] Sent: Tuesday, September 11, 2012 4:28 PM To: mat...@li... Subject: [Matplotlib-users] a memory leak in matplotlib plot embedded inwxpython I'm using matplotlib plots embedded in a wxpython application to display a stream of data. The application works effectively but I have noticed that memory usage rises substantially over time (if left long enough the process can go from 50MB to near 1GB of RAM). After some experimentation, I have tracked the problem down to the canvas.draw() call needed to refresh my matplotlib plos. Thinking that the problem may be due to how I coded up my plots I looked to see if the problem was present in the examples given at http://matplotlib.sourceforge.net/examples/user_interfaces and found that the problem seem to be present in some the examples posted there if I added a timer to cause the canvas draw to be repeatedly performed. The example below is based on http://matplotlib.sourceforge.net/examples/user_interfaces/embedding_in_ wx2.html and has been instrumented to report memory usage when running in Windows. My tests indicate that working set memory rises by 11 to 12 Kbytes at each plot. Some what to my surprise, I found the same issue when I ran an even simpler version on a linux mint virtual box running on my win7 system. (I have not explored this much so somebody else might want to test things on a non virtual linux box) I assume this implies that python is probably keeping something alive that was expected to be automatically cleaned up at each draw. I have made some effort to localize the problem further but right now I don't have the necessary time to get heavily into the inner workings of matplotlib or wxpython Has any body else seen this problem before, and if so, has any body a work around that allows rapid replotting - I would guess that I could periodically flush the figure and re build my plots but this would cause periodic glitches in plotting? Dominic System details Win7 ultimate service pack1 Python 2.6.6 (but I've seen the problem with python2.5 and 2.7) Matplotlib 1.1.1 (but also in earlier versions) Wxpython 2.9.4.0 msw (classic) (put also on 2.8.12.0 unicode) Example ------------------------------------------------------------------------ ----------------------------------------------------------- import wxversion wxversion.ensureMinimal('2.8') from numpy import arange, sin, pi import matplotlib # uncomment the following to use wx rather than wxagg #matplotlib.use('WX') #from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas # comment out the following to use wx rather than wxagg matplotlib.use('WXAgg') from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas from matplotlib.backends.backend_wx import NavigationToolbar2Wx from matplotlib.figure import Figure import win32process import wx class CanvasFrame(wx.Frame): def __init__(self): wx.Frame.__init__(self,None,-1, 'CanvasFrame',size=(550,350)) #self.SetBackgroundColour(wx.NamedColor("WHITE")) # 2.9 does not like self.figure = Figure() self.axes = self.figure.add_subplot(111) t = arange(0.0,3.0,0.01) s = sin(2*pi*t) self.axes.plot(t,s) self.canvas = FigureCanvas(self, -1, self.figure) self.sizer = wx.BoxSizer(wx.VERTICAL) self.sizer.Add(self.canvas, 1, wx.LEFT | wx.TOP | wx.GROW) self.SetSizer(self.sizer) self.Fit() self.add_toolbar() # comment this out for no toolbar self.timer = wx.Timer(self, -1) self.Bind(wx.EVT_TIMER, self.OnUpdate) self.delay = 200 self.timer.Start(self.delay, oneShot = False) self.proc_id = win32process.GetCurrentProcess() adict = win32process.GetProcessMemoryInfo(self.proc_id) self.memory_old = adict["WorkingSetSize"] self.i = 0 def add_toolbar(self): self.toolbar = NavigationToolbar2Wx(self.canvas) self.toolbar.Realize() if wx.Platform == '__WXMAC__': # Mac platform (OSX 10.3, MacPython) does not seem to cope with # having a toolbar in a sizer. This work-around gets the buttons # back, but at the expense of having the toolbar at the top self.SetToolBar(self.toolbar) else: # On Windows platform, default window size is incorrect, so set # toolbar width to figure width. tw, th = self.toolbar.GetSizeTuple() fw, fh = self.canvas.GetSizeTuple() # By adding toolbar in sizer, we are able to put it at the bottom # of the frame - so appearance is closer to GTK version. # As noted above, doesn't work for Mac. self.toolbar.SetSize(wx.Size(fw, th)) self.sizer.Add(self.toolbar, 0, wx.LEFT | wx.EXPAND) # update the axes menu on the toolbar self.toolbar.update() def OnUpdate(self, evt): self.OnPaint( evt) self.i +=1 the_count =25 if self.i %the_count ==0: adict_now = win32process.GetProcessMemoryInfo(self.proc_id) memory_now = adict_now["WorkingSetSize"] delta = (memory_now - self.memory_old )/ (the_count *1024.0) #convert to kbytes per update self.memory_old = memory_now print "memory now = %i delta = %f\n" %(memory_now, delta) def OnPaint(self, event): self.canvas.draw() class App(wx.App): def OnInit(self): 'Create the main window and insert the custom frame' frame = CanvasFrame() frame.Show(True) return True app = App(0) app.MainLoop() |
