sun.awt.X11.XEvent is creating 600 MB of char[] for no good reason (original) (raw)

Federico Tello Gentile federicotg at gmail.com
Wed Oct 26 15:05:14 PDT 2011

Here's a patch to use StringBuilder. It also sets an initial size to reduce char[] copying when appending.

I ran the generator locally and checked the generated code.

As I don't know if those java files are generated on every build or if they were generated just once with certain input files and committed to the repo, I did not go any further.

I hope it is at least a starting point.

El jue, 27-10-2011 a las 00:14 +0400, Oleg Sukhodolsky escribió:

Yep, you are right. It is a WrapperGenerator who should be fixed. And after that we need to regenerate all wrappers (if they are not generated during build).

Oleg. On Wed, Oct 26, 2011 at 11:27 PM, Federico <federicotg at gmail.com> wrote: > Almost all sun.awt.X11.XWrapperBase subclasses have similarly horrible > getFieldsAsString() implementations, but they are all automatically > generated (which is a relief as there was no human being actually > writing such code). > > They all say at the beginning: > > // This file is an automatically generated file, please do not edit > this file, modify the WrapperGenerator.java file instead ! > > My guess is in file > /openjdk/jdk/src/solaris/classes/sun/awt/X11/generator/WrapperGenerator.java > > in line 678 > public void writeToString(StructType stp, PrintWriter pw) { > > starts the code generating bit. > > > 2011/10/26 Oleg Sukhodolsky <son.two at gmail.com>: >> +1 to Artem. >> >> It is better to fix this too. >> >> Oleg. >> >> On Wed, Oct 26, 2011 at 7:34 PM, Artem Ananiev <artem.ananiev at oracle.com> wrote: >>> >>> On 10/26/2011 7:26 PM, Anthony Petrov wrote: >>>> >>>> On 10/26/2011 7:12 PM, Artem Ananiev wrote: >>>>> >>>>> On 10/21/2011 4:00 PM, Anthony Petrov wrote: >>>>>> >>>>>> Indeed, this is a nasty issue. Thanks for spotting it. You may notice >>>>>> that in most other places where something is logged, the code usually >>>>>> checks whether logging is enabled for a certain level of logging, e.g.: >>>>>> >>>>>>> if (shapeLog.isLoggable(PlatformLogger.FINER)) { >>>>>>> shapeLog.finer( >>>>>>> "*** INFO: Setting shape: PEER: " + this >>>>>>> + "; WINDOW: " + getWindow() >>>>>>> + "; TARGET: " + target >>>>>>> + "; SHAPE: " + shape); >>>>>>> } >>>>>> >>>>>> So basically, we could simply wrap the line in question into a similar >>>>>> if(){} statement to make sure it gets executed only when the FINEST >>>>>> level of logging is enabled. A similar solution may also apply to >>>>>> another call to enableLog.finer() in the same method just a few lines >>>>>> below. >>>>> >>>>> Although the fix has been already pushed to the workspace, let me >>>>> wonder if, in addition to wrapping the logging calls with the "if ()" >>>>> checks, we should have also rewritten isEventDisabled() to use >>>>> StringBuilder? >>>> >>>> I guess you really mean the XEvent.getFieldsAsString() here [1], right? >>> >>> Yes, exactly. Thanks for this correction. >>> >>>> Possibly. But with Federico's fix this method now only gets called when >>>> logging is enabled, and as such the impact of the issue is limited. >>> >>> I realize that. My point is that we just hide the problem, or make it less >>> visible, or make it appear less frequently - whatever you prefer. However, >>> the problematic code that contains char[] allocation is still in the >>> workspace, and we know how often people use the current code as a pattern >>> for future changes... >>> >>> Thanks, >>> >>> Artem >>> >>>> [1] >>>> http://mail.openjdk.java.net/pipermail/awt-dev/2011-October/001952.html >>>> >>>> -- >>>> best regards, >>>> Anthony >>>> >>>> >>>>> >>>>> Thanks, >>>>> >>>>> Artem >>>>> >>>>>> Could you make a patch, test it, and post it to this mailing list for >>>>>> review please? >>>>>> >>>>>> -- >>>>>> best regards, >>>>>> Anthony >>>>>> >>>>>> On 10/21/2011 7:10 AM, Federico Tello Gentile wrote: >>>>>>> >>>>>>> Hi. >>>>>>> I'm running >>>>>>> >>>>>>> java -version >>>>>>> java version "1.7.0147-icedtea" >>>>>>> OpenJDK Runtime Environment (IcedTea7 2.0pre) >>>>>>> (7b147-2.0pre6-1ubuntu1) >>>>>>> OpenJDK 64-Bit Server VM (build 21.0-b17, mixed mode) >>>>>>> >>>>>>> and profiling a simple Swing application. >>>>>>> >>>>>>> Just by opening a JFrame and moving the mouse over it for 10 secods I >>>>>>> see 600 MB of char[] being created. I can easily create several >>>>>>> terabytes or those if I move the mouse a little longer. Thanks to the >>>>>>> incredibly efficient garbage collector the application performance is >>>>>>> not visibly affected on my 4GB quad core machine. >>>>>>> >>>>>>> The problem is an incredibly inefficient method >>>>>>> sun.awt.X11.XEvent.getFieldsAsString() which I pasted at the end of >>>>>>> this >>>>>>> message. >>>>>>> >>>>>>> The way it it handling string concatenation forces StringBuilder to >>>>>>> grow >>>>>>> many times and ends up calling Arrays.copyOf a lot of times. >>>>>>> It is being called by the sun.awt.X11.XWrapperBase.toString() just for >>>>>>> the sake of logging here: >>>>>>> >>>>>>> sun.awt.X11.XComponentPeer >>>>>>> >>>>>>> protected boolean isEventDisabled(XEvent e) >>>>>>> >>>>>>> enableLog.finest("Component is {1}, checking for disabled event >>>>>>> {0}", e, >>>>>>> (isEnabled()?"enabled":"disable")); >>>>>>> >>>>>>> The worse part is that even if logging is disabled and nothing at >>>>>>> all is >>>>>>> ever logged, the toString is called anyway and all those char[] are >>>>>>> created anyway. >>>>>>> >>>>>>> Here's a NetBeans profiler memory snapshot. >>>>>>> >>>>>>> http://ubuntuone.com/4xkprEzadUM4sUSdAnWlN5 >>>>>>> >>>>>>> >>>>>>> This does not happen at all if I run the same profiling with this >>>>>>> openjdk version >>>>>>> >>>>>>> java -version >>>>>>> java version "1.6.023" >>>>>>> OpenJDK Runtime Environment (IcedTea6 1.11pre) (6b23~pre10-0ubuntu5) >>>>>>> OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode) >>>>>>> >>>>>>> I hope we can do something to improve this situation. I guess all Swing >>>>>>> applications are affected. >>>>>>> >>>>>>> I look forward for any comments. >>>>>>> >>>>>>> Here's the "thing"... >>>>>>> >>>>>>> --------------------------------------------------- >>>>>>> >>>>>>> String getFieldsAsString() { >>>>>>> String ret=""; >>>>>>> >>>>>>> ret += ""+"type = " + XlibWrapper.eventToString[gettype()] +", "; >>>>>>> ret += ""+"xany = " + getxany() +", "; >>>>>>> ret += ""+"xkey = " + getxkey() +", "; >>>>>>> ret += ""+"xbutton = " + getxbutton() +", "; >>>>>>> ret += ""+"xmotion = " + getxmotion() +", "; >>>>>>> ret += ""+"xcrossing = " + getxcrossing() +", "; >>>>>>> ret += ""+"xfocus = " + getxfocus() +", "; >>>>>>> ret += ""+"xexpose = " + getxexpose() +", "; >>>>>>> ret += ""+"xgraphicsexpose = " + getxgraphicsexpose() +", "; >>>>>>> ret += ""+"xnoexpose = " + getxnoexpose() +", "; >>>>>>> ret += ""+"xvisibility = " + getxvisibility() +", "; >>>>>>> ret += ""+"xcreatewindow = " + getxcreatewindow() +", "; >>>>>>> ret += ""+"xdestroywindow = " + getxdestroywindow() +", "; >>>>>>> ret += ""+"xunmap = " + getxunmap() +", "; >>>>>>> ret += ""+"xmap = " + getxmap() +", "; >>>>>>> ret += ""+"xmaprequest = " + getxmaprequest() +", "; >>>>>>> ret += ""+"xreparent = " + getxreparent() +", "; >>>>>>> ret += ""+"xconfigure = " + getxconfigure() +", "; >>>>>>> ret += ""+"xgravity = " + getxgravity() +", "; >>>>>>> ret += ""+"xresizerequest = " + getxresizerequest() +", "; >>>>>>> ret += ""+"xconfigurerequest = " + getxconfigurerequest() +", "; >>>>>>> ret += ""+"xcirculate = " + getxcirculate() +", "; >>>>>>> ret += ""+"xcirculaterequest = " + getxcirculaterequest() +", "; >>>>>>> ret += ""+"xproperty = " + getxproperty() +", "; >>>>>>> ret += ""+"xselectionclear = " + getxselectionclear() +", "; >>>>>>> ret += ""+"xselectionrequest = " + getxselectionrequest() +", "; >>>>>>> ret += ""+"xselection = " + getxselection() +", "; >>>>>>> ret += ""+"xcolormap = " + getxcolormap() +", "; >>>>>>> ret += ""+"xclient = " + getxclient() +", "; >>>>>>> ret += ""+"xmapping = " + getxmapping() +", "; >>>>>>> ret += ""+"xerror = " + getxerror() +", "; >>>>>>> ret += ""+"xkeymap = " + getxkeymap() +", "; >>>>>>> ret += "{" + getpad(0) + " " + getpad(1) + " " + getpad(2) + " " + >>>>>>> getpad(3) + " " + getpad(4) + " " + getpad(5) + " " + getpad(6) + " >>>>>>> " + getpad(7) + " " + getpad(8) + " " + getpad(9) + " " + >>>>>>> getpad(10) >>>>>>> + " " + getpad(11) + " " + getpad(12) + " " + getpad(13) + " " + >>>>>>> getpad(14) + " " + getpad(15) + " " + getpad(16) + " " + getpad(17) >>>>>>> + " " + getpad(18) + " " + getpad(19) + " " + getpad(20) + " " + >>>>>>> getpad(21) + " " + getpad(22) + " " + getpad(23) + " " + "}"; >>>>>>> return ret; >>>>>>> } >>>>>>> >>>>>>> >>> >> >

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