Hi,
My first thought would be that if we're running interpreted then we are already
deep in the hole performance wise. If in addition we are class loading and
initializing then our performance should be dominated by IO, a much deeper
hole.
This isn't to say that class initializing cost isn't important, but it feels
like this would be best addressed by not running such code interpreted at all —
at runtime — but generating some blueprints at compile time which unpack into
the objects using a VM wide shared hot loop.
Sent from Outlook
On Mon, Nov 9, 2015 at 12:45 PM -0800, "Stuart Marks" <stuart.ma...@oracle.com>
wrote:
Hi Michael, Peter,
I admit to not having followed all the benchmarking discussion (travel, Devoxx)
but I did want to respond to this:
Peter wrote:
> So it looks like that there's no need to burden the public API with explicit
> argument overloads.
These are JMH benchmarks, which take care to warm up the JIT, so that
everything
is nicely optimized, inlined, escape-analyzed, etc., right?
If so, I don't see this at all being representative of how these APIs will be
used. They won't be called in tight loops that give the JVM a chance to
optimize
them. Instead, they'll be used for initializing fields, including static fields:
class MyClass {
static final Set set = Set.of("a", "b", "c");
...
}
This call to Set.of() will (probably) be called exactly once when MyClass is
loaded. It'll probably be run in interpretive mode. If the API becomes popular,
there will be lots of calls like this in static initializers and instance
initializers. Most of these will be called once or relatively few times, but
there may be a lot of such calls. I think most of these would be run by the
interpreter.
How do we assess the impact of fixed-args vs varargs overloads for cases like
this?
s'marks
