$ $ java -Xbootclasspath/p:dist/nashorn.jar -jar dist/nashorn.jar test/script/basic/run-octane.js -- test/script/external/octane/pdfjs.js --verbose --iterations 100 2>&1 | tee pdfjs.log
command line: running pdfjs.js...
Score: 156
Score: 160
Score: 153
Score: 147
Score: 128
Score: 113
Score: 120
Score: 122
Score: 114
Score: 117
Score: 106
Score: 111
Score: 107
Score: 105
Score: 94.4
Score: 99.8
Score: 94.3
Score: 94.7
Score: 92.3
Score: 90.3
Score: 86.5
Score: 84.6
Score: 83.3
Score: 73.2

The sampling profiling shows most of the time at the end is spent at PropertyListenerManager.removePropertyListener, which does the linear scan across all listeners.

Heap dumps show the significant amount of memory is consumed by NativeObject$Prototype.listeners, which appears to be the same instance against which the hottest call is made. On the first iterations, there are about 1M listeners, by the end of the run, there are 15M+.