YJIT: Make ratio_in_yjit always available (#8064)

internal/vm.h

@@ -76,6 +76,11 @@ VALUE rb_lambda_call(VALUE obj, ID mid, int argc, const VALUE *argv,
                      VALUE data2);
 void rb_check_stack_overflow(void);
 
+#if USE_YJIT
+/* vm_exec.c */
+extern uint64_t rb_vm_insns_count;
+#endif
+
 /* vm_insnhelper.c */
 VALUE rb_equal_opt(VALUE obj1, VALUE obj2);
 VALUE rb_eql_opt(VALUE obj1, VALUE obj2);

vm_exec.c

@@ -11,6 +11,11 @@
 
 #include <math.h>
 
+#if USE_YJIT
+// The number of instructions executed on vm_exec_core. --yjit-stats uses this.
+uint64_t rb_vm_insns_count = 0;
+#endif
+
 #if VM_COLLECT_USAGE_DETAILS
 static void vm_analysis_insn(int insn);
 #endif

vm_insnhelper.h

@@ -20,8 +20,11 @@ RUBY_EXTERN rb_serial_t ruby_vm_global_cvar_state;
 # define RJIT_STATS RUBY_DEBUG
 #endif
 
-#if YJIT_STATS
-#define YJIT_COLLECT_USAGE_INSN(insn) rb_yjit_collect_vm_usage_insn(insn)
+#if USE_YJIT // We want vm_insns_count on any YJIT-enabled build
+// Increment vm_insns_count for --yjit-stats. We increment this even when
+// --yjit or --yjit-stats is not used because branching to skip it is slower.
+// We also don't use ATOMIC_INC for performance, allowing inaccuracy on Ractors.
+#define YJIT_COLLECT_USAGE_INSN(insn) rb_vm_insns_count++
 #else
 #define YJIT_COLLECT_USAGE_INSN(insn) // none
 #endif

yjit.h

@@ -30,7 +30,6 @@ bool rb_yjit_compile_new_iseqs(void);
 unsigned rb_yjit_call_threshold(void);
 void rb_yjit_invalidate_all_method_lookup_assumptions(void);
 void rb_yjit_cme_invalidate(rb_callable_method_entry_t *cme);
-void rb_yjit_collect_vm_usage_insn(int insn);
 void rb_yjit_collect_binding_alloc(void);
 void rb_yjit_collect_binding_set(void);
 bool rb_yjit_compile_iseq(const rb_iseq_t *iseq, rb_execution_context_t *ec);
@@ -53,7 +52,6 @@ static inline bool rb_yjit_compile_new_iseqs(void) { return false; }
 static inline unsigned rb_yjit_call_threshold(void) { return UINT_MAX; }
 static inline void rb_yjit_invalidate_all_method_lookup_assumptions(void) {}
 static inline void rb_yjit_cme_invalidate(rb_callable_method_entry_t *cme) {}
-static inline void rb_yjit_collect_vm_usage_insn(int insn) {}
 static inline void rb_yjit_collect_binding_alloc(void) {}
 static inline void rb_yjit_collect_binding_set(void) {}
 static inline bool rb_yjit_compile_iseq(const rb_iseq_t *iseq, rb_execution_context_t *ec) { return false; }

yjit.rb

@@ -167,14 +167,11 @@ module RubyVM::YJIT
     # Average length of instruction sequences executed by YJIT
     avg_len_in_yjit = total_exits > 0 ? retired_in_yjit.to_f / total_exits : 0
 
-    # This only available on yjit stats builds
-    if stats.key?(:vm_insns_count)
-      # Proportion of instructions that retire in YJIT
-      total_insns_count = retired_in_yjit + stats[:vm_insns_count]
-      yjit_ratio_pct = 100.0 * retired_in_yjit.to_f / total_insns_count
-      stats[:total_insns_count] = total_insns_count
-      stats[:ratio_in_yjit] = yjit_ratio_pct
-    end
+    # Proportion of instructions that retire in YJIT
+    total_insns_count = retired_in_yjit + stats[:vm_insns_count]
+    yjit_ratio_pct = 100.0 * retired_in_yjit.to_f / total_insns_count
+    stats[:total_insns_count] = total_insns_count
+    stats[:ratio_in_yjit] = yjit_ratio_pct
 
     # Make those stats available in RubyVM::YJIT.runtime_stats as well
     stats[:side_exit_count]  = side_exits
@@ -318,14 +315,10 @@ module RubyVM::YJIT
       out.puts "object_shape_count:    " + format_number(13, stats[:object_shape_count])
       out.puts "side_exit_count:       " + format_number(13, stats[:side_exit_count])
       out.puts "total_exit_count:      " + format_number(13, stats[:total_exit_count])
-      out.puts "total_insns_count:     " + format_number(13, stats[:total_insns_count]) if stats.key?(:total_insns_count)
-      if stats.key?(:vm_insns_count)
-        out.puts "vm_insns_count:        " + format_number(13, stats[:vm_insns_count])
-      end
+      out.puts "total_insns_count:     " + format_number(13, stats[:total_insns_count])
+      out.puts "vm_insns_count:        " + format_number(13, stats[:vm_insns_count])
       out.puts "yjit_insns_count:      " + format_number(13, stats[:exec_instruction])
-      if stats.key?(:ratio_in_yjit)
-        out.puts "ratio_in_yjit:         " + ("%12.1f" % stats[:ratio_in_yjit]) + "%"
-      end
+      out.puts "ratio_in_yjit:         " + ("%12.1f" % stats[:ratio_in_yjit]) + "%"
       out.puts "avg_len_in_yjit:       " + ("%13.1f" % stats[:avg_len_in_yjit])
 
       print_sorted_exit_counts(stats, out: out, prefix: "exit_")

yjit/bindgen/src/main.rs

@@ -357,6 +357,9 @@ fn main() {
         .allowlist_function("rb_ivar_defined")
         .allowlist_function("rb_ivar_get")
 
+        // From internal/vm.h
+        .allowlist_var("rb_vm_insns_count")
+
         // From include/ruby/internal/intern/vm.h
         .allowlist_function("rb_get_alloc_func")
 

yjit/src/cruby_bindings.inc.rs

@@ -1135,6 +1135,7 @@ extern "C" {
         n: ::std::os::raw::c_long,
         elts: *const VALUE,
     ) -> VALUE;
+    pub static mut rb_vm_insns_count: u64;
     pub fn rb_method_entry_at(obj: VALUE, id: ID) -> *const rb_method_entry_t;
     pub fn rb_callable_method_entry(klass: VALUE, id: ID) -> *const rb_callable_method_entry_t;
     pub fn rb_callable_method_entry_or_negative(

yjit/src/stats.rs

@@ -369,7 +369,6 @@ make_counters! {
     binding_allocations,
     binding_set,
 
-    vm_insns_count,
     compiled_iseq_entry,
     compiled_iseq_count,
     compiled_blockid_count,
@@ -507,7 +506,6 @@ fn rb_yjit_gen_stats_dict(context: bool) -> VALUE {
 
     let hash = unsafe { rb_hash_new() };
 
-    // CodeBlock stats
     unsafe {
         // Get the inline and outlined code blocks
         let cb = CodegenGlobals::get_inline_cb();
@@ -547,6 +545,9 @@ fn rb_yjit_gen_stats_dict(context: bool) -> VALUE {
             hash_aset_usize!(hash, "live_context_count", live_context_count);
             hash_aset_usize!(hash, "live_context_size", live_context_count * context_size);
         }
+
+        // VM instructions count
+        hash_aset_usize!(hash, "vm_insns_count", rb_vm_insns_count as usize);
     }
 
     // If we're not generating stats, the hash is done
@@ -566,13 +567,6 @@ fn rb_yjit_gen_stats_dict(context: bool) -> VALUE {
             let counter_ptr = get_counter_ptr(counter_name);
             let counter_val = *counter_ptr;
 
-            #[cfg(not(feature = "stats"))]
-            if counter_name == &"vm_insns_count" {
-                // If the stats feature is disabled, we don't have vm_insns_count
-                // so we are going to exclude the key
-                continue;
-            }
-
             // Put counter into hash
             let key = rust_str_to_sym(counter_name);
             let value = VALUE::fixnum_from_usize(counter_val as usize);
@@ -750,12 +744,6 @@ pub extern "C" fn rb_yjit_reset_stats_bang(_ec: EcPtr, _ruby_self: VALUE) -> VAL
     return Qnil;
 }
 
-/// Increment the number of instructions executed by the interpreter
-#[no_mangle]
-pub extern "C" fn rb_yjit_collect_vm_usage_insn() {
-    incr_counter!(vm_insns_count);
-}
-
 #[no_mangle]
 pub extern "C" fn rb_yjit_collect_binding_alloc() {
     incr_counter!(binding_allocations);