G1 log traces: rounding errors!

[Andreas Müller]

Hi all,

has anybody ever noticed that the G1 collector (in Java 7 with larger heaps) writes gc.log traces like that:
433.966: [GC pause (young) 13G->12G(16G), 0.0431884 secs]
I am a bit concerned about the rounding errors when I use those traces to do a quantitative analysis:(
What about that GC trace line:
417.747: [GC pause (young) 12G->12G(16G), 0.0443063 secs]
I am sure that the collector did some work here, but any meaningful parsing of that line must come to the conclusion that 0 bytes of heap have been freed.
On the other hand, I find traces like this one:
48.809: [GC pause (young) 10G->9981M(16G), 0.0607958 secs]

Is there any information about the rounding policy in these traces?

Best regards
Andreas

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