[erlang-bugs] Regression in erlang:system_monitor long_gc ?

Chris Newcombe <>
Wed Oct 22 22:21:57 CEST 2008

Hi OTP team,

I'm using  R12B-2  (erts 5.6.2).   I'm using erlang:system_monitor to
detect long_gc times.

I very often see long_gc times mis-reported as >4,200 seconds, e.g.

   system_monitor: {1224,701965,21022}: system_monitor: killing
<0.149.0> as received

I searched the mailing-list archives, and someone else reported this
back in July
but I couldn't find any response.

I found an entry in very old release notes an apparently identical bug
was fixed in R9.

  1.9 ERTS 5.3.3
  When using erlang:system_monitor(Pid,{long_gc,Time}), and the GC
time exceeded 1 second, it sometimes erroneously showed up as about
4300 seconds. This bug has now been corrected.
Own Id: OTP-4903 Aux Id: seq8379

Please could this be fixed?  system_monitor is extremely useful in
production systems :)

many thanks,

Chris Newcombe

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