YJIT: try request count warmup heuristic

Make req count configurable through options

yjit/src/options.rs

@@ -13,6 +13,11 @@ pub struct Options {
  // Threshold==1 means compile on first execution
  pub call_threshold: usize,
 
+ // How many compilation requests to skip before compiling new code
+ // This is used to let some execution proceed when we are compiling
+ // a lot of new code, to make warmup more gradual for heavy workloads
+ pub jit_interv: usize,
+
  // Generate versions greedily until the limit is hit
  pub greedy_versioning: bool,
 
@@ -56,6 +61,7 @@ pub struct Options {
 pub static mut OPTIONS: Options = Options {
  exec_mem_size: 128 * 1024 * 1024,
  call_threshold: 30,
+ jit_interv: 120,
  greedy_versioning: false,
  no_type_prop: false,
  max_versions: 4,
@@ -139,6 +145,13 @@ pub fn parse_option(str_ptr: *const std::os::raw::c_char) -> Option<()> {
  }
  },
 
+ ("jit-interv", _) => match opt_val.parse() {
+ Ok(n) => unsafe { OPTIONS.jit_interv = n },
+ Err(_) => {
+ return None;
+ }
+ },
+
  ("max-versions", _) => match opt_val.parse() {
  Ok(n) => unsafe { OPTIONS.max_versions = n },
  Err(_) => {

yjit/src/yjit.rs

@@ -7,14 +7,17 @@ use crate::stats::YjitExitLocations;
 use crate::stats::incr_counter;
 
 use std::os::raw;
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 
 /// For tracking whether the user enabled YJIT through command line arguments or environment
 /// variables. AtomicBool to avoid `unsafe`. On x86 it compiles to simple movs.
 /// See <https://doc.rust-lang.org/std/sync/atomic/enum.Ordering.html>
 /// See [rb_yjit_enabled_p]
 static YJIT_ENABLED: AtomicBool = AtomicBool::new(false);
 
+/// How many compilation requests YJIT received in total
+static YJIT_REQUEST_COUNT: AtomicUsize = AtomicUsize::new(0);
+
 /// When false, we don't compile new iseqs, but might still service existing branch stubs.
 static COMPILE_NEW_ISEQS: AtomicBool = AtomicBool::new(false);
 
@@ -49,10 +52,20 @@ pub fn yjit_enabled_p() -> bool {
 #[no_mangle]
 pub extern "C" fn rb_yjit_threshold_hit(iseq: IseqPtr) -> bool {
 
- let call_threshold = get_option!(call_threshold) as u64;
  let total_calls = unsafe { rb_get_iseq_body_total_calls(iseq) } as u64;
 
- return total_calls == call_threshold;
+ if total_calls < get_option!(call_threshold) as u64 {
+ return false;
+ }
+
+ // Increment the request count
+ let req_count: usize = YJIT_REQUEST_COUNT.fetch_add(1, Ordering::Relaxed);
+
+ if req_count % get_option!(jit_interv) == 0 {
+ return true;
+ }
+
+ return false;
 }
 
 /// This function is called from C code