Tuning the Erlang VM

[jlouis]

Simple standard tunings of the Erlang VM cuts processing time in half here on my Linux Core i7 machine:

erl +P 2000000 +sbt db +sbwt very_long +swt very_low +sub true +Mulmbcs 32767 +Mumbcgs 1 +Musmbcs 2047

This makes the system lock the schedulers to physical cores so your kernel threads are not jumping around like mad. It also tells the VM to allocate carriers for memory in blocks of 32 megabytes and to use 2048 kilobyte blocks inside there. This means you get superpages in the TLB and you have way fewer TLB hits in the long run :)

[witeman]

I am using Erlang v19.0 in Windows 7, i7-5600U, there is no significant difference between your turning parameters and the original one 'erl +P 2000000', original one costs around 1763ms, while your turning one costs around 1700ms.

[jlouis]

Two immediate comments:

• The above won't work in a VM. It requires you have precise control over the "raw steel".
• I'm quite sure many of those parameters are no-ops on Windows, so you will probably need some Unix-derivative to get these to work.