[erlang-questions] couchdb performace 10x: using NIF for file io

Joel Reymont <>
Sun Oct 24 16:43:16 CEST 2010


On Oct 24, 2010, at 3:30 PM, Martin Scholl wrote:

> I'd guess this is because the NIF blocks the current VM thread instead
> of a dedicated I/O thread.

+A 4 is used by default and using +A 16 reduces the spikes

http://graphs.mikeal.couchone.com/#/graph/62b286fbb7aa55a4b0c4cc913c011c14

This is the latest 2.66ghz Core i7 MacBook Pro, 8gb memory and a 2 year-old 256gb Apple SSD.

The number of cores is reported as 2 but, obviously, a lot of threads end up waiting.

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