YJIT: Change the default mem size to 64MiB (#6912)

* YJIT: Change the default mem size to 64MiB

* Also update ruby --help

Co-authored-by: Alan Wu <XrXr@users.noreply.github.com>

NEWS.md

@@ -602,7 +602,7 @@ The following deprecated APIs are removed.
     * Simply run ruby with `--yjit-stats` to compute and dump stats (incurs some run-time overhead).
 * YJIT is now optimized to take advantage of object shapes. [[Feature #18776]]
 * Take advantage of finer-grained constant invalidation to invalidate less code when defining new constants. [[Feature #18589]]
-* The default `--yjit-exec-mem-size` is changed to 128 (MiB).
+* The default `--yjit-exec-mem-size` is changed to 64 (MiB).
 * The default `--yjit-call-threshold` is changed to 30.
 
 ### MJIT

ruby.c

@@ -340,7 +340,7 @@ usage(const char *name, int help, int highlight, int columns)
 #if YJIT_STATS
         M("--yjit-stats",              "", "Enable collecting YJIT statistics"),
 #endif
-        M("--yjit-exec-mem-size=num",  "", "Size of executable memory block in MiB (default: 256)"),
+        M("--yjit-exec-mem-size=num",  "", "Size of executable memory block in MiB (default: 64)"),
         M("--yjit-call-threshold=num", "", "Number of calls to trigger JIT (default: 10)"),
         M("--yjit-max-versions=num",   "", "Maximum number of versions per basic block (default: 4)"),
         M("--yjit-greedy-versioning",  "", "Greedy versioning mode (default: disabled)"),

yjit/src/options.rs

@@ -49,7 +49,7 @@ pub struct Options {
 
 // Initialize the options to default values
 pub static mut OPTIONS: Options = Options {
-    exec_mem_size: 128 * 1024 * 1024,
+    exec_mem_size: 64 * 1024 * 1024,
     call_threshold: 30,
     greedy_versioning: false,
     no_type_prop: false,