Do you have specifics on that matter ?
GHC Haskell is an advanced optimising compiler that will produce considerably faster functional code than both Erlang and Java. For maximum performance, it is perfectly possible to write imperative array-oriented code in Haskell, in which case performance should be comparable to Java.
Please consider all the things Phil Trinder likely knows about GHC ;-)
So it's a good thing that those "benchmarks do not compare like-for-like" because that allows the inclusion of idiomatic Haskell code?
It's a useful resource, but I think we should we wary of making very general remarks based on the results.
The benchmarks game is not restricted to "the idiomatic style" so it isn't a problem that "the idiomatic style" for a particular problem is often not clear.
> Many of the Haskell solutions also look quite old…
We would be very happy to accept new programs:
https://salsa.debian.org/benchmarksgame-team/benchmarksgame/...
(1) Cloud Haskell is primarily designed for execution on distributed memory architectures where the messages pass over a network. So expect that the it would show high communication latency in the first PingPing benchmark.
(2) GHC Haskell processes are lightweight, i.e. maintained in the GHC Runtime Environment, and elsewhere in this discussion called fibres. So expect that it would have fast process creation and be able to sustain a large maximum number of processes (second benchmark).
(3) It's hard to speculate on throughput (third benchmark). The high communication latency may be hidden in a steady state by having multiple requests in the network. Haskell execution time is slower than many languages, but is probably comparable with Erlang and Scala.