[Fwd: RE: BIFs vs. reductions]

Zoltan Peter Toth <>
Thu Feb 10 12:56:56 CET 2005


Hi,
I post Erik's reply as it didn't seem to reach the list.

Meanwhile I took a look at other BIFs, like ets:lookup/2
which seems to count as cca. 60 reductions, and length that
is cca. 30, (28) _independently_ of the lists's actual length.

Considering that processes are rescheduled after executing 1000
reductions (is it still so ?), does this mean that a process using some
BIFs on very long lists can get much more real CPU time than another
using short lists ?
	/Zoltan

-------- Original Message --------
Subject: RE: BIFs vs. reductions
Date: Tue, 8 Feb 2005 15:58:35 +0100
From: Erik Stenman <>
To: Zoltán Péter Tóth (IJ/ETH)  <>
CC: 

> Hi,
> 
> Can someone tell me if BIFs always count as one Erlang reduction ?

No, e.g. append counts as 20 no matter the length of the list!
(At least it used to.)

> (returned from process_info)
> Is there an exact definition of what counts as a reduction ?

No.

Erik





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