Add an easy work to work out if you are on an optimizing runtime

[chrisseaton]

We want to avoid people running JRuby+Truffle on a standard JVM, or even a JVM with Graal but the wrong flags, and being disappointed about performance. When JRuby+Truffle starts we check that the TruffleRuntime is a Graal runtime, and if it isn't we present a warning. Doing this requires looking at the undocumented runtime name.

Truffle.getRuntime().getName().toLowerCase(Locale.ENGLISH).contains("graal");

I wonder if it would be useful to add a method boolean isOptimizing() to TruffleRuntime. This hides the implementation detail that it is Graal being used, and leaves the door open for any other hypothetical optimising Truffle runtimes, while still allowing us to show our warning.

Another option would be the inverse - boolean isInterpreter().

[chumer]

I don't like isInterpreter as the GraalRuntime also uses an interpreter.

I also don't like isOptimizing because it does not match the term compilation that we use everywhere else (CompilerDirectives, CompilerAsserts).

boolean isCompiling() does not sound very compelling either, because it has an ambiguous meaning. Also isOptimizing might be misinterpreted as "does it optimize at the moment?".

So I'd propose: boolean isCompilingRuntime() instead.

[chrisseaton]

I'm fine with isCompilingRuntime. I'll leave this open for a few days to see if anyone else has any opinions.

[woess]

I'd propose isOptimizingRuntime().

[chrisseaton]

Maybe doesOptimize or doesCompile?

[jtulach]

There already is isProfilingEnabled and as far as I know it does exactly what is being requested.

[chrisseaton]

I didn't know about that. I don't think it's exactly the same thing, as you could chose to run Graal with optimisation but no profiling, but I think you're right I can repurpose for a basic check to see if people have got Graal.

[smarr]

I would also like to have a proper isOptimizingRuntime(). I think this is very useful to avoid issues on the user level.

And isProfilingEnabled() is not the right way forward. In Graal it depends on TruffleCompilerOptions.TruffleProfilingEnabled. And, its name and documentation very clearly state that it is something different.

[woess]

IMHO, isProfilingEnabled isn't really a property of the runtime but should be an independent option, e.g. TruffleOptions.Profiling. I'd rather have an isOptimizingRuntime() instead of isProfilingEnabled(). @chumer may have a different opinion.

[chumer]

@woess yes my opinion is that these things should not be merged.

[jtulach]

How many more isXYZ methods do you guys plan to introduce into TruffleRuntime? It seems to me that there is some duplication in having both isProfilingEnabled and isOptimizingRuntime.

If "isProfilingEnabled isn't really a property of the runtime but should be an independent option" - then current isProfilingEnabled == TruffleOptions.Profiling && isOptimizingRuntime() - how do we get rid of the redundant isProfilingEnabled method in TruffleRuntime then?

[smarr]

@jtulach it is TruffleCompilerOptions.TruffleProfilingEnabled. Thus, there is zero redundancy here, because the configuration is in com.oracle.graal.truffle and not part of the Truffle API.