User control over splitting granularity while parallel processing

[Aleksey Shipilev]

Hi Georgiy,

On 11/27/2012 08:00 PM, Georgiy Rakov wrote:
> The only useful thing I see is to enable user to specify computational
> resources to be excluded while processing pipelines or to assign
> particular set of resources to the given pipeline.

At this point, you can only limit the number of workers in FJP serving
the requests (which will have drastic impact on performance in lots of
other places).

> What do you think?

I think this requires:

 a) the exposure of CPU layout to Java code, which is need for multitude
of other stuff in JDK, including ProcessorLocals, NUMA-aware stuff, and
whatnot. I don't think it would be ready for JDK8, we can consider that
for JDK9 and retrofit the Stream API to leverage this Processor API.

 b) FJP to respect the affinity you describe, this probably is best
solved by applying the affinity to worker threads via Processor API.
Again, not in the scope of JDK8.

Thanks,
-Aleksey.