<AWT Dev> sun.awt.X11.XEvent is creating 600 MB of char[] for no good reason

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 "1.7.0_147-icedtea"
> >>>>>>> OpenJDK Runtime Environment (IcedTea7 2.0pre)
> >>>>>>> (7~b147-2.0~pre6-1ubuntu1)
> >>>>>>> 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 "1.6.0_23"
> >>>>>>> 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[get_type()] +", ";
> >>>>>>> ret += ""+"xany = " + get_xany() +", ";
> >>>>>>> ret += ""+"xkey = " + get_xkey() +", ";
> >>>>>>> ret += ""+"xbutton = " + get_xbutton() +", ";
> >>>>>>> ret += ""+"xmotion = " + get_xmotion() +", ";
> >>>>>>> ret += ""+"xcrossing = " + get_xcrossing() +", ";
> >>>>>>> ret += ""+"xfocus = " + get_xfocus() +", ";
> >>>>>>> ret += ""+"xexpose = " + get_xexpose() +", ";
> >>>>>>> ret += ""+"xgraphicsexpose = " + get_xgraphicsexpose() +", ";
> >>>>>>> ret += ""+"xnoexpose = " + get_xnoexpose() +", ";
> >>>>>>> ret += ""+"xvisibility = " + get_xvisibility() +", ";
> >>>>>>> ret += ""+"xcreatewindow = " + get_xcreatewindow() +", ";
> >>>>>>> ret += ""+"xdestroywindow = " + get_xdestroywindow() +", ";
> >>>>>>> ret += ""+"xunmap = " + get_xunmap() +", ";
> >>>>>>> ret += ""+"xmap = " + get_xmap() +", ";
> >>>>>>> ret += ""+"xmaprequest = " + get_xmaprequest() +", ";
> >>>>>>> ret += ""+"xreparent = " + get_xreparent() +", ";
> >>>>>>> ret += ""+"xconfigure = " + get_xconfigure() +", ";
> >>>>>>> ret += ""+"xgravity = " + get_xgravity() +", ";
> >>>>>>> ret += ""+"xresizerequest = " + get_xresizerequest() +", ";
> >>>>>>> ret += ""+"xconfigurerequest = " + get_xconfigurerequest() +", ";
> >>>>>>> ret += ""+"xcirculate = " + get_xcirculate() +", ";
> >>>>>>> ret += ""+"xcirculaterequest = " + get_xcirculaterequest() +", ";
> >>>>>>> ret += ""+"xproperty = " + get_xproperty() +", ";
> >>>>>>> ret += ""+"xselectionclear = " + get_xselectionclear() +", ";
> >>>>>>> ret += ""+"xselectionrequest = " + get_xselectionrequest() +", ";
> >>>>>>> ret += ""+"xselection = " + get_xselection() +", ";
> >>>>>>> ret += ""+"xcolormap = " + get_xcolormap() +", ";
> >>>>>>> ret += ""+"xclient = " + get_xclient() +", ";
> >>>>>>> ret += ""+"xmapping = " + get_xmapping() +", ";
> >>>>>>> ret += ""+"xerror = " + get_xerror() +", ";
> >>>>>>> ret += ""+"xkeymap = " + get_xkeymap() +", ";
> >>>>>>> ret += "{" + get_pad(0) + " " + get_pad(1) + " " + get_pad(2) + " " +
> >>>>>>> get_pad(3) + " " + get_pad(4) + " " + get_pad(5) + " " + get_pad(6) + "
> >>>>>>> " + get_pad(7) + " " + get_pad(8) + " " + get_pad(9) + " " +
> >>>>>>> get_pad(10)
> >>>>>>> + " " + get_pad(11) + " " + get_pad(12) + " " + get_pad(13) + " " +
> >>>>>>> get_pad(14) + " " + get_pad(15) + " " + get_pad(16) + " " + get_pad(17)
> >>>>>>> + " " + get_pad(18) + " " + get_pad(19) + " " + get_pad(20) + " " +
> >>>>>>> get_pad(21) + " " + get_pad(22) + " " + get_pad(23) + " " + "}";
> >>>>>>> return ret;
> >>>>>>> }
> >>>>>>>
> >>>>>>>
> >>>
> >>
> >

-- 
Mi clave pública
http://keyserver.ubuntu.com:11371/pks/lookup?op=get&search=0x157673683A51700A
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