Limit frequency of idle GCs
In a server process with a relatively large heap (100s of MB) serving regular but relatively infrequent requests (~1 per sec) the idle GC runs after essentially every request which turns out to be extremely expensive: switching it off takes us from approx. 30% CPU to approx. 0.3% CPU.
It is certainly useful have the GC run when idle but running it *every* time the process goes idle isn't necessary. It doesn't work to increase the delay (e.g. say
-I2) as then the idle GC would never run, because the requests are rather regular.
I'd quite like to be able to say something of the form "do a GC if idle for at least 0.3s as long as the idle GC has not run in the last 120s" - where 120s is another option passed to the RTS.
Does this sound like a reasonable idea?