[erlang-questions] hybrid heap question

Scott Lystig Fritchie <>
Thu Mar 1 04:31:44 CET 2007

>>>>> "uw" == Ulf Wiger <> writes:

uw> Does anyone else have some experience with SMP in OTP R11B-3?

My brief experience with Mnesia in a 1-CPU-running-100% machine in a
write-intensive workload(*) (to be in production use in a few months),
the same load on a dual Xeon EM64T box showed both CPUs near 100%
usage but very little change in total throughput.

My apologies to Dan G. for not following up on his Mnesia patch work
(I've been on a business trip for the last 10 days).  He'd witnessed a
similar pattern, and he suspects (if I recall correctly) lock
inefficiencies in the ETS internals.  {shrug}  If that's the case, I'm
a willing guinea pig for testing SMP-friendlier ETS and/or Mnesia


(*) 80% of transactions update at least one record, ouch!

(**) Sorry again, Dan!  I will be returning home tomorrow and will be
able to catch up shortly, I hope.

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