Comment 8 for bug 429476

In a run of this page from start until the animated map appears, this is the log of the times at which a GC was done:

2:214:GC t=0.175912
2:370:GC t=0.925824
2:595:GC t=1.469851
2:645:GC t=1.532591
2:2284:GC t=23.293265
2:10953:GC t=85.411238
2:11016:GC t=87.652958
2:11034:GC t=87.910751
2:11038:GC t=88.201925
2:11039:GC t=88.234485
2:11040:GC t=88.316330
2:11041:GC t=88.328484

As you can see, we go 20 seconds without any GC, and then 60 more after that until the next GC. Here are the last few calls to IsGCThresholdReached before the 23s GC:

IsGCThresholdReached t=18.488329 mb=7437487/33554432, gb=2427140/4390912
IsGCThresholdReached t=18.640668 mb=7439791/33554432, gb=2427140/4390912
IsGCThresholdReached t=18.869077 mb=7443295/33554432, gb=2427140/4390912
IsGCThresholdReached t=19.843841 mb=7446751/33554432, gb=2431236/4390912
IsGCThresholdReached t=19.930377 mb=7447423/33554432, gb=2431236/4390912
IsGCThresholdReached t=21.518867 mb=7450891/33554432, gb=2431236/4390912

'mb' is the mallocBytes (cur/max) and 'gb' is the gcBytes (cur/max). The last few calls just before the 85s GC are:

IsGCThresholdReached t=84.934737 mb=7226436/33554432, gb=7086000/34246720
IsGCThresholdReached t=84.935768 mb=7230504/33554432, gb=7090096/34246720
IsGCThresholdReached t=84.936678 mb=7234144/33554432, gb=7090096/34246720
IsGCThresholdReached t=84.937600 mb=7238212/33554432, gb=7094192/34246720
IsGCThresholdReached t=84.938453 mb=7241852/33554432, gb=7094192/34246720
IsGCThresholdReached t=84.942108 mb=7245272/33554432, gb=7098288/34246720

Whatever is causing the memory usage, it doesn't show up in the metrics used by IsGCThresholdReached, so we are not GC'ing.