[erlang-questions] Changing scheduler behaviour to make tests less deterministic

Rickard Green <>
Fri Dec 29 16:19:30 CET 2006

We'll consider it, but I'll give no promise. If we add it, it will most 
likely not make in into R11B-3.

Rickard Green, Erlang/OTP

Chris Newcombe wrote:
> Cool.  Would you consider adding maybe a '+Q nnnn' option to allow
> setting CONTEXT_REDS dyamically?   (The 'Q' would be mnemonic for
> 'quantum' as in scheduler quantum of course.)
> Many thanks,
> Chris
> On 12/27/06, Rickard Green <> wrote:
>> As of R11B-3 there will be a "modified timing" command line argument
>> to erl (+T). It will be possible to modify the timing more or less.
>> It will (most likely) do the following:
>> * spawn/spawn_link/spawn_opt will schedule out the parent process
>>   and with "heavier modified timing" force the parent to sleep
>>   for a while. (Among the few SMP bugs we have found in our Erlang
>>   code, most of them have been bugs where the code depended on the
>>   parent doing some initialization before the child began
>>   executing.)
>> * A fixed amount of reductions will be bumped as soon as a process
>>   is scheduled in.
>> BR,
>> Rickard Green, Erlang/OTP

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