Bug 194287

Description bugzilla 2007-06-25 15:28:38 EDT

When the display receives a lot of OS events, (a)syncExec calls do not get processed in a timely fashion. This happened specifically when using OLE automation to embed a flash movie that was using upto 100% of CPU. 

Looking at readAndDispatch() in Display it will only process these (a)syncExec calls if there are no OS messages to handle, so a busy activex object can and does starve the (a)syncExec call handling

I use the 3.2.2 stable release but tried also with 3.3RC4 which has the same problem. However, did not try the workaround on 3.3RC4 but Display.java code still looks the same.

A workaround with current stable version is to dispatch these (a)syncExec calls via a custom queueing mechanism on the display thread since they then get executed immediately by the synchronizer.

Something like;
            while(keepRunning) {
                Runnable r = null;
                synchronized(messageQueue) {
                    if(!messageQueue.isEmpty()) {
                        r = (Runnable)messageQueue.remove(0);
                    }
                }
                if(r != null) {
                    swtDisplay.syncExec(r);
                } 
            	
                if(!swtDisplay.readAndDispatch()) {
                    swtDisplay.sleep();
                }
            }