Feature #9953: set_trace_func values which could be frozen or symbols

• Status: Open
• Assignee: -
• Target version: -

[enebo (Thomas Enebo)]

I have been changing JRuby's tracing support internally and notice we churn through lots of extra Ruby objects per set_trace_func call. It strikes me that a couple of these values do not need to be allocated more than once. I propose:

1. event_type becomes a symbol (or could be single frozen string per distinct event type)
2. filename becomes a single frozen string per file (frozen per spec and possible single instance as impl-specific detail)

I find the value of these two values being mutable strings to be minimal and tracing speed will have less GC-pressure.

[ko1 (Koichi Sasada)]

Hi,

event_type becomes a symbol (or could be single frozen string per distinct event type)

Now, TracePoint#event returns symbol.
I think it is enough and set_trace_func should not be modified.

I have no objection to make strings frozen.

filename becomes a single frozen string per file (frozen per spec and possible single instance as impl-specific detail)

Again, I have no objection to make strings frozen.

(maybe nobody depends on such behavior)