YJIT: implement two-step call threshold (#8839)

* YJIT: implement two-step call threshold

Automatically switch call threshold to a larger value for
larger, production-sized apps, while still allowing smaller apps
and command-line programs to start with a lower threshold.

* Update yjit/src/options.rs

Co-authored-by: Alan Wu <[email protected]>

* Make the new variables constants

* Check that a custom call threshold was not specified

---------

Co-authored-by: Alan Wu <[email protected]>

1 files changed, 12 insertions, 3 deletions

diff --git a/yjit/src/options.rs b/yjit/src/options.rs
index fe0a7ec9cc..98c0548677 100644
--- a/yjit/src/options.rs
+++ b/yjit/src/options.rs
@@ -2,17 +2,26 @@ use std::{ffi::{CStr, CString}, ptr::null};
 use crate::backend::current::TEMP_REGS;
 use std::os::raw::{c_char, c_int, c_uint};
 
+// Call threshold for small deployments and command-line apps
+pub static SMALL_CALL_THRESHOLD: u64 = 30;
+
+// Call threshold for larger deployments and production-sized applications
+pub static LARGE_CALL_THRESHOLD: u64 = 120;
+
+// Number of live ISEQs after which we consider an app to be large
+pub static LARGE_ISEQ_COUNT: u64 = 40_000;
+
 // This option is exposed to the C side a a global variable for performance, see vm.c
 // Number of method calls after which to start generating code
 // Threshold==1 means compile on first execution
 #[no_mangle]
-static mut rb_yjit_call_threshold: u64 = 30;
+pub static mut rb_yjit_call_threshold: u64 = SMALL_CALL_THRESHOLD;
 
 // This option is exposed to the C side a a global variable for performance, see vm.c
 // Number of execution requests after which a method is no longer
 // considered hot. Raising this results in more generated code.
 #[no_mangle]
-static mut rb_yjit_cold_threshold: u64 = 200_000;
+pub static mut rb_yjit_cold_threshold: u64 = 200_000;
 
 // Command-line options
 #[derive(Clone, PartialEq, Eq, Debug)]
@@ -92,7 +101,7 @@ static YJIT_OPTIONS: [(&str, &str); 8] = [
     ("--yjit-trace-exits",              "Record Ruby source location when exiting from generated code"),
     ("--yjit-trace-exits-sample-rate",  "Trace exit locations only every Nth occurrence"),
     ("--yjit-exec-mem-size=num",        "Size of executable memory block in MiB (default: 128)"),
-    ("--yjit-call-threshold=num",       "Number of calls to trigger JIT (default: 30)"),
+    ("--yjit-call-threshold=num",       "Number of calls to trigger JIT"),
     ("--yjit-cold-threshold=num",       "Global call after which ISEQs not compiled (default: 200K)"),
     ("--yjit-max-versions=num",         "Maximum number of versions per basic block (default: 4)"),
     ("--yjit-perf",                     "Enable frame pointers and perf profiling"),