diff --git a/src/runtime/runtime-promise.cc b/src/runtime/runtime-promise.cc
index 1bc7eaa68c..4743a2d71d 100644
--- a/src/runtime/runtime-promise.cc
+++ b/src/runtime/runtime-promise.cc
@@ -80,10 +80,10 @@ RUNTIME_FUNCTION(Runtime_EnqueueMicrotask) {
   return ReadOnlyRoots(isolate).undefined_value();
 }
 
-RUNTIME_FUNCTION(Runtime_RunMicrotasks) {
+RUNTIME_FUNCTION(Runtime_PerformMicrotaskCheckpoint) {
   HandleScope scope(isolate);
   DCHECK_EQ(0, args.length());
-  isolate->RunMicrotasks();
+  MicrotasksScope::PerformCheckpoint(reinterpret_cast<v8::Isolate*>(isolate));
   return ReadOnlyRoots(isolate).undefined_value();
 }
 
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index fc8820ec80..53987e181a 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -230,7 +230,7 @@ namespace internal {
   F(ReportMessage, 1, 1)                           \
   F(ReThrow, 1, 1)                                 \
   F(RunMicrotaskCallback, 2, 1)                    \
-  F(RunMicrotasks, 0, 1)                           \
+  F(PerformMicrotaskCheckpoint, 0, 1)              \
   F(StackGuard, 0, 1)                              \
   F(Throw, 1, 1)                                   \
   F(ThrowApplyNonFunction, 1, 1)                   \
diff --git a/test/debugger/debug/es6/debug-promises/evaluate-across-microtasks.js b/test/debugger/debug/es6/debug-promises/evaluate-across-microtasks.js
index 71b07476d3..ec3555d22b 100644
--- a/test/debugger/debug/es6/debug-promises/evaluate-across-microtasks.js
+++ b/test/debugger/debug/es6/debug-promises/evaluate-across-microtasks.js
@@ -51,7 +51,7 @@ LogX("start")();
 // Make sure that the debug event listener was invoked.
 assertTrue(listenerComplete);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 var expectation =
   [ "[0] debugger", "[1] start", "[1] then 1",
diff --git a/test/debugger/debug/es6/debug-promises/proxy-as-promise.js b/test/debugger/debug/es6/debug-promises/proxy-as-promise.js
index 3bd1fead08..431837ceba 100644
--- a/test/debugger/debug/es6/debug-promises/proxy-as-promise.js
+++ b/test/debugger/debug/es6/debug-promises/proxy-as-promise.js
@@ -39,4 +39,4 @@ function listener(event, exec_state, event_data, data) {}
 Debug.setBreakOnUncaughtException();
 Debug.setListener(listener);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
diff --git a/test/debugger/debug/es6/debug-promises/reject-in-constructor-opt.js b/test/debugger/debug/es6/debug-promises/reject-in-constructor-opt.js
index 6b7abde111..2b8ebb1c0b 100644
--- a/test/debugger/debug/es6/debug-promises/reject-in-constructor-opt.js
+++ b/test/debugger/debug/es6/debug-promises/reject-in-constructor-opt.js
@@ -40,22 +40,22 @@ function bar(a,b) {
 }
 
 foo();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 foo();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 %OptimizeFunctionOnNextCall(foo);
 
 // bar likely gets inlined into foo.
 foo();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 %NeverOptimizeFunction(bar);
 %OptimizeFunctionOnNextCall(foo);
 
 // bar does not get inlined into foo.
 foo();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(0, expected_events);
diff --git a/test/debugger/debug/es8/async-debug-builtin-predictions.js b/test/debugger/debug/es8/async-debug-builtin-predictions.js
index 70f1b57e7e..bcd990896b 100644
--- a/test/debugger/debug/es8/async-debug-builtin-predictions.js
+++ b/test/debugger/debug/es8/async-debug-builtin-predictions.js
@@ -57,7 +57,7 @@ async function foo() {
 
 foo();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 Debug.setListener(null);
 Debug.clearBreakOnException();
diff --git a/test/debugger/debug/es8/async-debug-caught-exception-cases.js b/test/debugger/debug/es8/async-debug-caught-exception-cases.js
index f5c1ed98a8..24cf598439 100644
--- a/test/debugger/debug/es8/async-debug-caught-exception-cases.js
+++ b/test/debugger/debug/es8/async-debug-caught-exception-cases.js
@@ -197,7 +197,7 @@ function runPart(n) {
 
     events = 0;
     consumer(producer);
-    %RunMicrotasks();
+    %PerformMicrotaskCheckpoint();
 
     Debug.setListener(null);
     if (caught) {
diff --git a/test/debugger/debug/es8/async-debug-caught-exception.js b/test/debugger/debug/es8/async-debug-caught-exception.js
index 2feecc067f..de0c4e9c5b 100644
--- a/test/debugger/debug/es8/async-debug-caught-exception.js
+++ b/test/debugger/debug/es8/async-debug-caught-exception.js
@@ -37,7 +37,7 @@ log = [];
 Debug.setListener(listener);
 Debug.setBreakOnException();
 caught_throw();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 Debug.setListener(null);
 Debug.clearBreakOnException();
 assertEquals(["a"], log);
@@ -48,7 +48,7 @@ log = [];
 Debug.setListener(listener);
 Debug.setBreakOnUncaughtException();
 caught_throw();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 Debug.setListener(null);
 Debug.clearBreakOnUncaughtException();
 assertEquals([], log);
@@ -69,7 +69,7 @@ log = [];
 Debug.setListener(listener);
 Debug.setBreakOnException();
 caught_reject();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 Debug.setListener(null);
 Debug.clearBreakOnException();
 assertEquals([], log);
@@ -80,7 +80,7 @@ log = [];
 Debug.setListener(listener);
 Debug.setBreakOnUncaughtException();
 caught_reject();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 Debug.setListener(null);
 Debug.clearBreakOnUncaughtException();
 assertEquals([], log);
@@ -95,7 +95,7 @@ async function propagate_inner() { return thrower(); }
 async function propagate_outer() { return propagate_inner(); }
 
 propagate_outer();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(["a"], log);
 assertNull(exception);
 
@@ -104,7 +104,7 @@ log = [];
 async function propagate_await() { await 1; return thrower(); }
 async function propagate_await_outer() { return propagate_await(); }
 propagate_await_outer();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(["a"], log);
 assertNull(exception);
 
@@ -113,7 +113,7 @@ Debug.setBreakOnUncaughtException();
 
 log = [];
 Promise.resolve().then(() => Promise.reject()).catch(() => log.push("d")); // Exception c
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(["d"], log);
 assertNull(exception);
 
diff --git a/test/debugger/debug/es8/async-debug-step-abort-at-break.js b/test/debugger/debug/es8/async-debug-step-abort-at-break.js
index 85232b075b..47605cea16 100644
--- a/test/debugger/debug/es8/async-debug-step-abort-at-break.js
+++ b/test/debugger/debug/es8/async-debug-step-abort-at-break.js
@@ -48,6 +48,6 @@ debugger;            // B3 StepNext
 
 late_resolve(3);     // B4 Continue
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(5, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-continue-at-break.js b/test/debugger/debug/es8/async-debug-step-continue-at-break.js
index 60ea859ae3..79dcad6b1e 100644
--- a/test/debugger/debug/es8/async-debug-step-continue-at-break.js
+++ b/test/debugger/debug/es8/async-debug-step-continue-at-break.js
@@ -48,6 +48,6 @@ debugger;            // B3 Continue
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(5, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-in-and-out.js b/test/debugger/debug/es8/async-debug-step-in-and-out.js
index 737fced01a..5d64e5a10e 100644
--- a/test/debugger/debug/es8/async-debug-step-in-and-out.js
+++ b/test/debugger/debug/es8/async-debug-step-in-and-out.js
@@ -44,6 +44,6 @@ f();
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(4, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-in-out-out.js b/test/debugger/debug/es8/async-debug-step-in-out-out.js
index c1d8fd71be..7702742f58 100644
--- a/test/debugger/debug/es8/async-debug-step-in-out-out.js
+++ b/test/debugger/debug/es8/async-debug-step-in-out-out.js
@@ -44,6 +44,6 @@ f();
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(4, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-in.js b/test/debugger/debug/es8/async-debug-step-in.js
index d66714bc6c..fe84e4b9ba 100644
--- a/test/debugger/debug/es8/async-debug-step-in.js
+++ b/test/debugger/debug/es8/async-debug-step-in.js
@@ -44,6 +44,6 @@ f().then(value => assertEquals(4, value));
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(7, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-nested.js b/test/debugger/debug/es8/async-debug-step-nested.js
index f06da202f2..74432a6f52 100644
--- a/test/debugger/debug/es8/async-debug-step-nested.js
+++ b/test/debugger/debug/es8/async-debug-step-nested.js
@@ -51,6 +51,6 @@ f1();
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(6, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-next-constant.js b/test/debugger/debug/es8/async-debug-step-next-constant.js
index 4f4a154c9b..2b432632fa 100644
--- a/test/debugger/debug/es8/async-debug-step-next-constant.js
+++ b/test/debugger/debug/es8/async-debug-step-next-constant.js
@@ -32,6 +32,6 @@ async function f() {
 
 f();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(3, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-next.js b/test/debugger/debug/es8/async-debug-step-next.js
index 833bfc9c0d..0fdbd73f05 100644
--- a/test/debugger/debug/es8/async-debug-step-next.js
+++ b/test/debugger/debug/es8/async-debug-step-next.js
@@ -44,6 +44,6 @@ f();
 
 late_resolve(3);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(3, step_count);
diff --git a/test/debugger/debug/es8/async-debug-step-out.js b/test/debugger/debug/es8/async-debug-step-out.js
index 3ec6dd3490..d37ce5893e 100644
--- a/test/debugger/debug/es8/async-debug-step-out.js
+++ b/test/debugger/debug/es8/async-debug-step-out.js
@@ -42,6 +42,6 @@ f();
 
 late_resolve(3);   // B2 Continue
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(3, step_count);
diff --git a/test/debugger/debug/es8/debug-async-break-on-stack.js b/test/debugger/debug/es8/debug-async-break-on-stack.js
index df389f33d9..124cbabb8e 100644
--- a/test/debugger/debug/es8/debug-async-break-on-stack.js
+++ b/test/debugger/debug/es8/debug-async-break-on-stack.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
@@ -67,7 +67,7 @@ function setbreaks() {
 
 f();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEqualsAsync(2, async () => break_count);
 assertEqualsAsync(null, async () => exception);
diff --git a/test/debugger/debug/es8/debug-async-break.js b/test/debugger/debug/es8/debug-async-break.js
index 3e07ba9344..8a2982045a 100644
--- a/test/debugger/debug/es8/debug-async-break.js
+++ b/test/debugger/debug/es8/debug-async-break.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
@@ -65,7 +65,7 @@ Debug.setBreakPoint(f, 5);
 
 f();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEqualsAsync(3, async () => break_count);
 assertEqualsAsync(null, async () => exception);
diff --git a/test/debugger/debug/es8/debug-async-liveedit.js b/test/debugger/debug/es8/debug-async-liveedit.js
index 723a40f478..e85cbe3896 100644
--- a/test/debugger/debug/es8/debug-async-liveedit.js
+++ b/test/debugger/debug/es8/debug-async-liveedit.js
@@ -94,7 +94,7 @@ function patch(fun, from, to) {
   assertPromiseValue("Cat", promise);
   assertTrue(patch_attempted);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   // At this point one iterator is live, but closed, so the patch will succeed.
   patch(asyncfn, "'Cat'", "'Capybara'");
@@ -143,4 +143,4 @@ function patch(fun, from, to) {
                }));
 })();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
diff --git a/test/debugger/debug/es8/promise-finally.js b/test/debugger/debug/es8/promise-finally.js
index 6923e64f64..dc7833e6e8 100644
--- a/test/debugger/debug/es8/promise-finally.js
+++ b/test/debugger/debug/es8/promise-finally.js
@@ -35,7 +35,7 @@ Promise.resolve()
   .finally(() => thenable)
   .catch(e => caughtException = e);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 Debug.setListener(null);
 Debug.clearBreakOnException();
diff --git a/test/js-perf-test/AsyncAwait/baseline-babel-es2017.js b/test/js-perf-test/AsyncAwait/baseline-babel-es2017.js
index 1be3074f3b..37709d739b 100644
--- a/test/js-perf-test/AsyncAwait/baseline-babel-es2017.js
+++ b/test/js-perf-test/AsyncAwait/baseline-babel-es2017.js
@@ -160,10 +160,10 @@ function Setup() {
     return a;
   })();
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
 
 function Basic() {
   a();
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
diff --git a/test/js-perf-test/AsyncAwait/baseline-naive-promises.js b/test/js-perf-test/AsyncAwait/baseline-naive-promises.js
index f59ae86194..9b9c091a13 100644
--- a/test/js-perf-test/AsyncAwait/baseline-naive-promises.js
+++ b/test/js-perf-test/AsyncAwait/baseline-naive-promises.js
@@ -34,7 +34,7 @@ function Setup() {
   b = function b(p) { return p; };
   a = function a(p) { return p; };
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
 
 function Basic() {
@@ -48,5 +48,5 @@ function Basic() {
    .then(c)
    .then(b)
    .then(a);
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
diff --git a/test/js-perf-test/AsyncAwait/native.js b/test/js-perf-test/AsyncAwait/native.js
index 7979d2f4db..e9504c3a19 100644
--- a/test/js-perf-test/AsyncAwait/native.js
+++ b/test/js-perf-test/AsyncAwait/native.js
@@ -34,10 +34,10 @@ function Setup() {
   b = async function b() { return c(); };
   a = async function a() { return b(); };
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
 
 function Basic() {
   a();
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 }
diff --git a/test/js-perf-test/Inspector/debugger.js b/test/js-perf-test/Inspector/debugger.js
index 8e44aa7710..e9c862563b 100644
--- a/test/js-perf-test/Inspector/debugger.js
+++ b/test/js-perf-test/Inspector/debugger.js
@@ -69,7 +69,7 @@ function AsyncStacksInstrumentation() {
     p = p.then(nopCallback);
   }
   p = p.then(() => done = true);
-  while (!done) %RunMicrotasks();
+  while (!done) %PerformMicrotaskCheckpoint();
 }
 
 })();
diff --git a/test/js-perf-test/Modules/run.js b/test/js-perf-test/Modules/run.js
index e5f91e1aa9..4c038801a9 100644
--- a/test/js-perf-test/Modules/run.js
+++ b/test/js-perf-test/Modules/run.js
@@ -23,21 +23,21 @@ const iterations = 10000;
 function BasicExport() {
   let success = false;
   import("basic-export.js").then(m => { m.bench(); success = true; });
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   if (!success) throw new Error(666);
 }
 
 function BasicImport() {
   let success = false;
   import("basic-import.js").then(m => { m.bench(); success = true; });
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   if (!success) throw new Error(666);
 }
 
 function BasicNamespace() {
   let success = false;
   import("basic-namespace.js").then(m => { m.bench(); success = true; });
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   if (!success) throw new Error(666);
 }
 
diff --git a/test/mjsunit/code-coverage-block.js b/test/mjsunit/code-coverage-block.js
index 8cbb2969f7..bdba90cd1e 100644
--- a/test/mjsunit/code-coverage-block.js
+++ b/test/mjsunit/code-coverage-block.js
@@ -213,7 +213,7 @@ TestCoverage(
     nop();                                // 0100
   }                                       // 0150
 }();                                      // 0200
-%RunMicrotasks();                         // 0250
+%PerformMicrotaskCheckpoint();            // 0250
 `,
 [{"start":0,"end":299,"count":1},
  {"start":1,"end":201,"count":6},  // TODO(jgruber): Invocation count is off.
@@ -662,7 +662,7 @@ async function f() {                      // 0000
   await 42;                               // 0100
 };                                        // 0150
 f();                                      // 0200
-%RunMicrotasks();                         // 0250
+%PerformMicrotaskCheckpoint();            // 0250
 `,
 [{"start":0,"end":299,"count":1},
  {"start":0,"end":151,"count":3},
diff --git a/test/mjsunit/es6/microtask-delivery.js b/test/mjsunit/es6/microtask-delivery.js
index 6b239bea47..96035164f2 100644
--- a/test/mjsunit/es6/microtask-delivery.js
+++ b/test/mjsunit/es6/microtask-delivery.js
@@ -40,7 +40,7 @@ function assertArrayValues(expected, actual) {
 }
 
 function assertOrdering(expected) {
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertArrayValues(expected, ordering);
 }
 
diff --git a/test/mjsunit/es8/async-arrow-lexical-arguments.js b/test/mjsunit/es8/async-arrow-lexical-arguments.js
index b29f17fce0..720770ef49 100644
--- a/test/mjsunit/es8/async-arrow-lexical-arguments.js
+++ b/test/mjsunit/es8/async-arrow-lexical-arguments.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/es8/async-arrow-lexical-new.target.js b/test/mjsunit/es8/async-arrow-lexical-new.target.js
index 943267e9d8..7d016281f8 100644
--- a/test/mjsunit/es8/async-arrow-lexical-new.target.js
+++ b/test/mjsunit/es8/async-arrow-lexical-new.target.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/es8/async-arrow-lexical-super.js b/test/mjsunit/es8/async-arrow-lexical-super.js
index b15a3834db..b175ac5ae1 100644
--- a/test/mjsunit/es8/async-arrow-lexical-super.js
+++ b/test/mjsunit/es8/async-arrow-lexical-super.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/es8/async-arrow-lexical-this.js b/test/mjsunit/es8/async-arrow-lexical-this.js
index 38bdddc2c7..a21978d1a0 100644
--- a/test/mjsunit/es8/async-arrow-lexical-this.js
+++ b/test/mjsunit/es8/async-arrow-lexical-this.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/es8/async-await-basic.js b/test/mjsunit/es8/async-await-basic.js
index 6e9ee02ffe..1c7b2ac601 100644
--- a/test/mjsunit/es8/async-await-basic.js
+++ b/test/mjsunit/es8/async-await-basic.js
@@ -23,7 +23,7 @@ function assertThrowsAsync(run, errorType, message) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (!hadError) {
     throw new MjsUnitAssertionError(
@@ -57,7 +57,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
@@ -402,7 +402,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "a", "c"], log);
 }
 
@@ -416,7 +416,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "a", "c"], log);
 }
 
@@ -430,7 +430,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["a", "b", "c"], log);
 }
 
@@ -445,7 +445,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "c", "a"], log);
 }
 
@@ -459,7 +459,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "a", "c"], log);
 }
 
@@ -473,7 +473,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["a", "b", "c"], log);
 }
 
@@ -488,7 +488,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "a", "c"], log);
 }
 
@@ -502,7 +502,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "a", "c"], log);
 }
 
@@ -516,7 +516,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["a", "b", "c"], log);
 }
 
@@ -531,7 +531,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "c", "a"], log);
 }
 
@@ -545,7 +545,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["b", "c", "a"], log);
 }
 
@@ -559,7 +559,7 @@ assertDoesNotThrow(gaga);
     }
   }
   foo().then(() => log.push("c"));
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(["a", "b", "c"], log);
 }
 
@@ -585,7 +585,7 @@ assertDoesNotThrow(gaga);
 
   var ans;
   f2().then(x => ans = x).catch(e => ans = e);
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals([0], ans);
 }
 
diff --git a/test/mjsunit/es8/async-await-no-constructor.js b/test/mjsunit/es8/async-await-no-constructor.js
index e954e2ac57..5e4780a6ef 100644
--- a/test/mjsunit/es8/async-await-no-constructor.js
+++ b/test/mjsunit/es8/async-await-no-constructor.js
@@ -23,5 +23,5 @@ async function bar() {
 
 foo();
 bar();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(2, count);
diff --git a/test/mjsunit/es8/async-await-species.js b/test/mjsunit/es8/async-await-species.js
index b3e925433a..3fc46fd230 100644
--- a/test/mjsunit/es8/async-await-species.js
+++ b/test/mjsunit/es8/async-await-species.js
@@ -21,7 +21,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/es8/async-destructuring.js b/test/mjsunit/es8/async-destructuring.js
index 1fbac5a072..d5e90eb057 100644
--- a/test/mjsunit/es8/async-destructuring.js
+++ b/test/mjsunit/es8/async-destructuring.js
@@ -21,7 +21,7 @@ function assertThrowsAsync(run, errorType, message) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (!hadError) {
     throw new MjsUnitAssertionError(
@@ -55,7 +55,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
@@ -77,7 +77,7 @@ function assertEqualsAsync(expected, run, msg) {
   assertEquals(1, y);
   assertEquals(1, z);
   assertEquals(0, w);
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
   assertEquals(1, y);
   assertEquals(1, z);
   assertEquals(1, w);
diff --git a/test/mjsunit/es8/async-function-try-finally.js b/test/mjsunit/es8/async-function-try-finally.js
index 9ba07eb427..43badc480a 100644
--- a/test/mjsunit/es8/async-function-try-finally.js
+++ b/test/mjsunit/es8/async-function-try-finally.js
@@ -21,7 +21,7 @@ function assertThrowsAsync(run, errorType, message) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (!hadError) {
     throw new MjsUnitAssertionError(
@@ -55,7 +55,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
diff --git a/test/mjsunit/harmony/async-from-sync-iterator.js b/test/mjsunit/harmony/async-from-sync-iterator.js
index 2d6be098a2..e9dfe5d322 100644
--- a/test/mjsunit/harmony/async-from-sync-iterator.js
+++ b/test/mjsunit/harmony/async-from-sync-iterator.js
@@ -24,7 +24,7 @@ function assertThrowsAsync(run, errorType, message) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (!hadError) {
     throw new MjsUnitAssertionError(
@@ -185,7 +185,7 @@ class MyError extends Error {};
   testFailure = error;
 });
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 if (testFailed) {
   throw testFailure;
 }
@@ -619,7 +619,7 @@ if (testFailed) {
   testFailure = error;
 });
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 if (testFailed) {
   throw testFailure;
 }
@@ -663,7 +663,7 @@ if (testFailed) {
 
   // Cycle through `f` to extract iterator methods
   f().catch(function() { %AbortJS("No error should have occurred"); });
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   assertEquals(typeof extractedNext, "function");
   assertThrowsAsync(() => extractedNext.call(undefined), TypeError);
diff --git a/test/mjsunit/harmony/async-generators-basic.js b/test/mjsunit/harmony/async-generators-basic.js
index cf21d9a8c8..5ff7d25eea 100644
--- a/test/mjsunit/harmony/async-generators-basic.js
+++ b/test/mjsunit/harmony/async-generators-basic.js
@@ -21,7 +21,7 @@ function assertThrowsAsync(run, errorType, message) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (!hadError) {
     throw new MjsUnitAssertionError(
@@ -55,7 +55,7 @@ function assertEqualsAsync(expected, run, msg) {
 
   assertFalse(hadValue || hadError);
 
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (hadError) throw actual;
 
@@ -448,7 +448,7 @@ async function* asyncGeneratorForNestedResumeNext() {
 }
 it = asyncGeneratorForNestedResumeNext();
 it.next().then(logIterResult, AbortUnreachable);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "rootbeer", done: false },
   { value: "float", done: false },
@@ -464,7 +464,7 @@ let asyncGeneratorExprForNestedResumeNext = async function*() {
 };
 it = asyncGeneratorExprForNestedResumeNext();
 it.next().then(logIterResult, AbortUnreachable);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "first", done: false },
   { value: "second", done: false },
@@ -482,7 +482,7 @@ let asyncGeneratorMethodForNestedResumeNext = ({
 }).method;
 it = asyncGeneratorMethodForNestedResumeNext();
 it.next().then(logIterResult, AbortUnreachable);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "remember", done: false },
   { value: "the cant!", done: false },
@@ -498,7 +498,7 @@ let asyncGeneratorCallEvalForNestedResumeNext =
       yield await Resolver("rainbow!");`);
 it = asyncGeneratorCallEvalForNestedResumeNext();
 it.next().then(logIterResult, AbortUnreachable);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "reading", done: false },
   { value: "rainbow!", done: false },
@@ -514,7 +514,7 @@ let asyncGeneratorNewEvalForNestedResumeNext =
       yield await Resolver("BB!");`);
 it = asyncGeneratorNewEvalForNestedResumeNext();
 it.next().then(logIterResult, AbortUnreachable);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: 731, done: false },
   { value: "BB!", done: false },
@@ -536,7 +536,7 @@ async function* asyncGeneratorForNestedResumeThrow() {
 }
 it = asyncGeneratorForNestedResumeThrow();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   "throw1",
   "throw2",
@@ -556,7 +556,7 @@ let asyncGeneratorExprForNestedResumeThrow = async function*() {
 };
 it = asyncGeneratorExprForNestedResumeThrow();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   "throw3",
   "throw4",
@@ -578,7 +578,7 @@ let asyncGeneratorMethodForNestedResumeThrow = ({
 }).method;
 it = asyncGeneratorMethodForNestedResumeThrow();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   "throw5",
   "throw6",
@@ -598,7 +598,7 @@ let asyncGeneratorCallEvalForNestedResumeThrow =
       AbortUnreachable();`);
 it = asyncGeneratorCallEvalForNestedResumeThrow();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   "throw7",
   "throw8",
@@ -618,7 +618,7 @@ let asyncGeneratorNewEvalForNestedResumeThrow =
       AbortUnreachable();`);
 it = asyncGeneratorNewEvalForNestedResumeThrow();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   "throw9",
   "throw10",
@@ -636,7 +636,7 @@ async function* asyncGeneratorForNestedResumeReturn() {
 }
 it = asyncGeneratorForNestedResumeReturn();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "step1", done: false },
   { value: "step2", done: true },
@@ -651,7 +651,7 @@ let asyncGeneratorExprForNestedResumeReturn = async function*() {
 };
 it = asyncGeneratorExprForNestedResumeReturn();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "step3", done: false },
   { value: "step4", done: true },
@@ -668,7 +668,7 @@ let asyncGeneratorMethodForNestedResumeReturn = ({
 }).method;
 it = asyncGeneratorMethodForNestedResumeReturn();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "step5", done: false },
   { value: "step6", done: true },
@@ -683,7 +683,7 @@ let asyncGeneratorCallEvalForNestedResumeReturn =
       yield "step7";`);
 it = asyncGeneratorCallEvalForNestedResumeReturn();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "step7", done: false },
   { value: "step8", done: true },
@@ -698,7 +698,7 @@ let asyncGeneratorNewEvalForNestedResumeReturn =
       yield "step9";`);
 it = asyncGeneratorNewEvalForNestedResumeReturn();
 it.next().then(logIterResult, logError);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals([
   { value: "step9", done: false },
   { value: "step10", done: true },
diff --git a/test/mjsunit/harmony/for-await-of.js b/test/mjsunit/harmony/for-await-of.js
index e23758a5e1..1b4fcd701a 100644
--- a/test/mjsunit/harmony/for-await-of.js
+++ b/test/mjsunit/harmony/for-await-of.js
@@ -1257,7 +1257,7 @@ let testFailure;
   testFailure = error;
 });
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 if (testFailed) {
   throw testFailure;
diff --git a/test/mjsunit/harmony/import-from-compilation-errored.js b/test/mjsunit/harmony/import-from-compilation-errored.js
index 3c99498d0e..49570b51de 100644
--- a/test/mjsunit/harmony/import-from-compilation-errored.js
+++ b/test/mjsunit/harmony/import-from-compilation-errored.js
@@ -7,7 +7,7 @@
 var error1, error2;
 import('modules-skip-12.js').catch(e => error1 = e);
 import('modules-skip-12.js').catch(e => error2 = e);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(error1, error2);
 assertInstanceof(error1, SyntaxError);
diff --git a/test/mjsunit/harmony/import-from-evaluation-errored.js b/test/mjsunit/harmony/import-from-evaluation-errored.js
index 3623091777..87dbc0a6aa 100644
--- a/test/mjsunit/harmony/import-from-evaluation-errored.js
+++ b/test/mjsunit/harmony/import-from-evaluation-errored.js
@@ -7,7 +7,7 @@
 var error1, error2;
 import('modules-skip-11.js').catch(e => error1 = e);
 import('modules-skip-11.js').catch(e => error2 = e);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(error1, error2);
 assertEquals(typeof error1, "symbol");
diff --git a/test/mjsunit/harmony/import-from-fetch-errored.js b/test/mjsunit/harmony/import-from-fetch-errored.js
index f3db881eb2..6d6510fcde 100644
--- a/test/mjsunit/harmony/import-from-fetch-errored.js
+++ b/test/mjsunit/harmony/import-from-fetch-errored.js
@@ -7,7 +7,7 @@
 var error1, error2;
 import('no-such-file').catch(e => error1 = e);
 import('no-such-file').catch(e => error2 = e);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(error1, error2);
 assertEquals(typeof error1, "string");
diff --git a/test/mjsunit/harmony/import-from-instantiation-errored.js b/test/mjsunit/harmony/import-from-instantiation-errored.js
index 2a481d5965..2cdbaaea32 100644
--- a/test/mjsunit/harmony/import-from-instantiation-errored.js
+++ b/test/mjsunit/harmony/import-from-instantiation-errored.js
@@ -7,7 +7,7 @@
 var error1, error2;
 import('modules-skip-10.js').catch(e => error1 = e);
 import('modules-skip-10.js').catch(e => error2 = e);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(error1, error2);
 assertInstanceof(error1, SyntaxError);
diff --git a/test/mjsunit/harmony/modules-import-1.js b/test/mjsunit/harmony/modules-import-1.js
index 7fd567f56f..f62d4d7b32 100644
--- a/test/mjsunit/harmony/modules-import-1.js
+++ b/test/mjsunit/harmony/modules-import-1.js
@@ -7,6 +7,6 @@
 var life;
 import('modules-skip-1.js').then(namespace => life = namespace.life());
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(42, life);
diff --git a/test/mjsunit/harmony/modules-import-10.js b/test/mjsunit/harmony/modules-import-10.js
index 68e000a131..eda4aaf7f9 100644
--- a/test/mjsunit/harmony/modules-import-10.js
+++ b/test/mjsunit/harmony/modules-import-10.js
@@ -9,7 +9,7 @@ import('modules-skip-6.js').then(namespace => life = namespace.life);
 
 assertEquals(undefined, Object.life);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(42, Object.life);
 assertEquals("42", life);
diff --git a/test/mjsunit/harmony/modules-import-11.js b/test/mjsunit/harmony/modules-import-11.js
index a5afa10048..ffba6a0722 100644
--- a/test/mjsunit/harmony/modules-import-11.js
+++ b/test/mjsunit/harmony/modules-import-11.js
@@ -18,5 +18,5 @@ async function test() {
 }
 
 test();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-12.js b/test/mjsunit/harmony/modules-import-12.js
index bcb8569221..d898c984ad 100644
--- a/test/mjsunit/harmony/modules-import-12.js
+++ b/test/mjsunit/harmony/modules-import-12.js
@@ -15,5 +15,5 @@ async function test() {
 }
 
 test();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-13.js b/test/mjsunit/harmony/modules-import-13.js
index 1cec1cce61..52518350ba 100644
--- a/test/mjsunit/harmony/modules-import-13.js
+++ b/test/mjsunit/harmony/modules-import-13.js
@@ -19,7 +19,7 @@ async function test1() {
 }
 
 test1();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
 
 ran = false;
@@ -36,5 +36,5 @@ async function test2() {
 }
 
 test2();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-14.js b/test/mjsunit/harmony/modules-import-14.js
index 3849c54c59..32b307eb3b 100644
--- a/test/mjsunit/harmony/modules-import-14.js
+++ b/test/mjsunit/harmony/modules-import-14.js
@@ -22,5 +22,5 @@ async function test() {
 }
 
 test();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-15.js b/test/mjsunit/harmony/modules-import-15.js
index 32255ce980..d041add3db 100644
--- a/test/mjsunit/harmony/modules-import-15.js
+++ b/test/mjsunit/harmony/modules-import-15.js
@@ -17,7 +17,7 @@ async function test1() {
 }
 
 test1();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
 
 ran = false;
@@ -37,7 +37,7 @@ async function test2() {
 }
 
 test2();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
 
 ran = false;
@@ -53,5 +53,5 @@ async function test3() {
 }
 
 test3();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-16.js b/test/mjsunit/harmony/modules-import-16.js
index 94510d48fc..18ad445a84 100644
--- a/test/mjsunit/harmony/modules-import-16.js
+++ b/test/mjsunit/harmony/modules-import-16.js
@@ -12,7 +12,7 @@ var body = "import('modules-skip-1.js').then(ns => { x = ns.life();" +
 var func = new Function(body);
 func();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(42, x);
 assertTrue(ran);
 
@@ -21,7 +21,7 @@ var body = "import('modules-skip-1.js').then(ns => { x = ns.life();" +
     " ran = true;} ).catch(err => %AbortJS(err))"
 eval("var func = new Function(body); func();");
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(42, x);
 assertTrue(ran);
 
@@ -31,6 +31,6 @@ var body = "eval(import('modules-skip-1.js').then(ns => { x = ns.life();" +
 var func = new Function(body);
 func();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(42, x);
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-17.js b/test/mjsunit/harmony/modules-import-17.js
index f73aa68f3b..606ebcd385 100644
--- a/test/mjsunit/harmony/modules-import-17.js
+++ b/test/mjsunit/harmony/modules-import-17.js
@@ -6,6 +6,6 @@
 
 var ns;
 import('modules-skip-13.js').then(x => ns = x);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(42, ns.default);
 assertEquals(ns, ns.self);
diff --git a/test/mjsunit/harmony/modules-import-2.js b/test/mjsunit/harmony/modules-import-2.js
index f50a5c8c53..a3fe0bc601 100644
--- a/test/mjsunit/harmony/modules-import-2.js
+++ b/test/mjsunit/harmony/modules-import-2.js
@@ -12,7 +12,7 @@ import('modules-skip-2.js').catch(err => msg = err.message);
 assertEquals(undefined, life);
 assertEquals(undefined, msg);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertEquals(42, life);
 assertEquals('42 is not the answer', msg);
diff --git a/test/mjsunit/harmony/modules-import-3.js b/test/mjsunit/harmony/modules-import-3.js
index 669f820fd7..d8cbe2a228 100644
--- a/test/mjsunit/harmony/modules-import-3.js
+++ b/test/mjsunit/harmony/modules-import-3.js
@@ -17,6 +17,6 @@ async function foo () {
 
 foo();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-5.js b/test/mjsunit/harmony/modules-import-5.js
index d9237828fe..c868a0c63f 100644
--- a/test/mjsunit/harmony/modules-import-5.js
+++ b/test/mjsunit/harmony/modules-import-5.js
@@ -9,5 +9,5 @@ let x = 'modules-skip-1.js';
 import(x).then(namespace => life = namespace.life());
 x = 'modules-skip-2.js';
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(42, life);
diff --git a/test/mjsunit/harmony/modules-import-6.js b/test/mjsunit/harmony/modules-import-6.js
index 6a5b7c8b5b..02fdf1b5fa 100644
--- a/test/mjsunit/harmony/modules-import-6.js
+++ b/test/mjsunit/harmony/modules-import-6.js
@@ -25,5 +25,5 @@ async function test() {
 
 test();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-7.js b/test/mjsunit/harmony/modules-import-7.js
index d0105112f4..8df8ddcdb2 100644
--- a/test/mjsunit/harmony/modules-import-7.js
+++ b/test/mjsunit/harmony/modules-import-7.js
@@ -19,6 +19,6 @@ async function test() {
 
 test();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-8.js b/test/mjsunit/harmony/modules-import-8.js
index 4417f0eb78..ac21a8c9e9 100644
--- a/test/mjsunit/harmony/modules-import-8.js
+++ b/test/mjsunit/harmony/modules-import-8.js
@@ -43,7 +43,7 @@ async function test1() {
 
 test1();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertTrue(ran);
 
@@ -66,7 +66,7 @@ async function test2() {
 
 test2();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertTrue(ran);
 
@@ -86,6 +86,6 @@ async function test3() {
 
 test3();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/modules-import-9.js b/test/mjsunit/harmony/modules-import-9.js
index 6794311305..664416f0eb 100644
--- a/test/mjsunit/harmony/modules-import-9.js
+++ b/test/mjsunit/harmony/modules-import-9.js
@@ -18,5 +18,5 @@ async function test() {
 }
 
 test();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(ran);
diff --git a/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-and-cleared-weakref.js b/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-and-cleared-weakref.js
index a7105771b3..66058e8bcd 100644
--- a/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-and-cleared-weakref.js
+++ b/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-and-cleared-weakref.js
@@ -25,7 +25,7 @@ let weak_ref;
 })();
 
 // Clear the KeepDuringJob set.
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 weak_ref.deref();
 o = null;
@@ -37,7 +37,7 @@ gc();
 wf.cleanupSome();
 assertEquals(0, cleanup_count);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 // This GC detects the WeakRef as dirty.
diff --git a/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-weakref.js b/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-weakref.js
index fb113bef0d..d6d9373094 100644
--- a/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-weakref.js
+++ b/test/mjsunit/harmony/weakrefs/cleanupsome-dereffed-weakref.js
@@ -25,7 +25,7 @@ let weak_ref;
 })();
 
 // Clear the KeepDuringJob set.
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 weak_ref.deref();
 o = null;
@@ -37,7 +37,7 @@ gc();
 wf.cleanupSome();
 assertEquals(0, cleanup_count);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 // Now the WeakRef can be cleared.
@@ -51,7 +51,7 @@ assertEquals(weak_ref, cleanup_cells[0]);
 // The cleanup task is not executed again since all WeakCells have been
 // processed.
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertEquals(1, cleanup_count);
diff --git a/test/mjsunit/harmony/weakrefs/cleanupsome-weakref.js b/test/mjsunit/harmony/weakrefs/cleanupsome-weakref.js
index ab1e7ebe19..d478aaab8c 100644
--- a/test/mjsunit/harmony/weakrefs/cleanupsome-weakref.js
+++ b/test/mjsunit/harmony/weakrefs/cleanupsome-weakref.js
@@ -31,7 +31,7 @@ gc();
 wf.cleanupSome();
 assertEquals(0, cleanup_count);
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 // Now the WeakRef can be cleared.
diff --git a/test/mjsunit/harmony/weakrefs/clear-after-deref.js b/test/mjsunit/harmony/weakrefs/clear-after-deref.js
index e76ff0011f..9577f48b05 100644
--- a/test/mjsunit/harmony/weakrefs/clear-after-deref.js
+++ b/test/mjsunit/harmony/weakrefs/clear-after-deref.js
@@ -28,7 +28,7 @@ let wr;
 gc();
 assertNotEquals(undefined, wr.deref());
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // New turn.
 
 let o = wr.deref();
diff --git a/test/mjsunit/harmony/weakrefs/two-weakrefs.js b/test/mjsunit/harmony/weakrefs/two-weakrefs.js
index 067578f29b..7109d51fde 100644
--- a/test/mjsunit/harmony/weakrefs/two-weakrefs.js
+++ b/test/mjsunit/harmony/weakrefs/two-weakrefs.js
@@ -38,7 +38,7 @@ gc();
   assertNotEquals(undefined, wr2.deref());
 })();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // New turn.
 
 assertEquals(0, cleanup_count);
@@ -47,7 +47,7 @@ wr1.deref();
 o1 = null;
 gc(); // deref makes sure we don't clean up wr1
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // New turn.
 
 assertEquals(0, cleanup_count);
@@ -56,7 +56,7 @@ wr2.deref();
 o2 = null;
 gc(); // deref makes sure we don't clean up wr2
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // New turn.
 
 assertEquals(1, cleanup_count);
@@ -64,7 +64,7 @@ assertEquals(wr1, cleared_cells1[0]);
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // New turn.
 
 assertEquals(2, cleanup_count);
diff --git a/test/mjsunit/harmony/weakrefs/weakcell-and-weakref.js b/test/mjsunit/harmony/weakrefs/weakcell-and-weakref.js
index 4e5eec018b..fc400169d0 100644
--- a/test/mjsunit/harmony/weakrefs/weakcell-and-weakref.js
+++ b/test/mjsunit/harmony/weakrefs/weakcell-and-weakref.js
@@ -34,12 +34,12 @@ gc();
   assertNotEquals(undefined, weak_ref.deref());
 })();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertTrue(cleanup_called);
diff --git a/test/mjsunit/harmony/weakrefs/weakref-creation-keeps-alive.js b/test/mjsunit/harmony/weakrefs/weakref-creation-keeps-alive.js
index fd22345104..02313fe761 100644
--- a/test/mjsunit/harmony/weakrefs/weakref-creation-keeps-alive.js
+++ b/test/mjsunit/harmony/weakrefs/weakref-creation-keeps-alive.js
@@ -33,14 +33,14 @@ gc();
   assertNotEquals(undefined, wr.deref());
 })();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertFalse(cleanup_called);
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertTrue(cleanup_called);
diff --git a/test/mjsunit/harmony/weakrefs/weakref-deref-keeps-alive.js b/test/mjsunit/harmony/weakrefs/weakref-deref-keeps-alive.js
index c67dc0a11b..05917c5261 100644
--- a/test/mjsunit/harmony/weakrefs/weakref-deref-keeps-alive.js
+++ b/test/mjsunit/harmony/weakrefs/weakref-deref-keeps-alive.js
@@ -29,12 +29,12 @@ let strong = {a: wr.deref(), b: wr_control.deref()};
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 // We have a strong reference to the objects, so the WeakRefs are not cleared yet.
@@ -57,7 +57,7 @@ gc();
   assertEquals(undefined, wr_control.deref());
 })();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertEquals(1, cleanup_count);
@@ -66,7 +66,7 @@ assertEquals(wc, cleanup_cells[0]);
 
 gc();
 
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 // Next turn.
 
 assertEquals(2, cleanup_count);
diff --git a/test/mjsunit/regress/regress-5405.js b/test/mjsunit/regress/regress-5405.js
index eeab479384..e21818c880 100644
--- a/test/mjsunit/regress/regress-5405.js
+++ b/test/mjsunit/regress/regress-5405.js
@@ -11,7 +11,7 @@ let log = [];
     return 10;
   }
 })();
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 
 (function() {
   with ({get ['.new.target']() { log.push('new.target') }}) {
diff --git a/test/mjsunit/regress/regress-5691.js b/test/mjsunit/regress/regress-5691.js
index 6cda92ca79..b460ac4b99 100644
--- a/test/mjsunit/regress/regress-5691.js
+++ b/test/mjsunit/regress/regress-5691.js
@@ -18,6 +18,6 @@ Promise.resolve(Promise.resolve()).then(() => log += "|fast-resolve");
 (class extends Promise {}).resolve(Promise.resolve()).then(() => log += "|slow-resolve");
 
 log += "|start";
-  %RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals("|start|turn1|fast-resolve|turn2|turn3|slow-resolve|turn4\n\
 |start|turn1|fast-resolve|turn2|turn3|slow-resolve|turn4", result);
diff --git a/test/mjsunit/regress/regress-682349.js b/test/mjsunit/regress/regress-682349.js
index d94e0691d6..f82f242f03 100644
--- a/test/mjsunit/regress/regress-682349.js
+++ b/test/mjsunit/regress/regress-682349.js
@@ -9,5 +9,5 @@ function f() {
   success = (f.caller === null);
 }
 Promise.resolve().then(f);
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(success);
diff --git a/test/mjsunit/regress/regress-740694.js b/test/mjsunit/regress/regress-740694.js
index f07eb1b3a7..6f31fef0c7 100644
--- a/test/mjsunit/regress/regress-740694.js
+++ b/test/mjsunit/regress/regress-740694.js
@@ -17,6 +17,6 @@ var error;
 var promise = __f_0();
 promise.then(assertUnreachable,
              err => { done = true; error = err });
-%RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertTrue(error.startsWith('Error reading'));
 assertTrue(done);
diff --git a/test/mjsunit/regress/regress-797581.js b/test/mjsunit/regress/regress-797581.js
index eb87e67128..3dfad4c463 100644
--- a/test/mjsunit/regress/regress-797581.js
+++ b/test/mjsunit/regress/regress-797581.js
@@ -17,7 +17,7 @@ function TryToLoadModule(filename, expect_error, token) {
   }
 
   import(filename).catch(SetError);
-  %RunMicrotasks();
+  %PerformMicrotaskCheckpoint();
 
   if (expect_error) {
     assertTrue(caught_error instanceof SyntaxError);
diff --git a/test/mjsunit/regress/regress-800651.js b/test/mjsunit/regress/regress-800651.js
index c6410f702e..05e31fe4ca 100644
--- a/test/mjsunit/regress/regress-800651.js
+++ b/test/mjsunit/regress/regress-800651.js
@@ -27,5 +27,5 @@ function g() {
   let namespace = Promise.resolve().then(importUndefined);
 }
 g();
-  %RunMicrotasks();
+%PerformMicrotaskCheckpoint();
 assertEquals(list, [1,2]);
diff --git a/test/mjsunit/test-async.js b/test/mjsunit/test-async.js
index d4fee9bfb9..8f7b553988 100644
--- a/test/mjsunit/test-async.js
+++ b/test/mjsunit/test-async.js
@@ -80,7 +80,7 @@ var testAsync;
     }
 
     drainMicrotasks() {
-      %RunMicrotasks();
+      %PerformMicrotaskCheckpoint();
     }
 
     done_() {
@@ -111,7 +111,7 @@ var testAsync;
   testAsync = function(test, name) {
     let assert = new AsyncAssertion(test, name);
     test(assert);
-    %RunMicrotasks();
+    %PerformMicrotaskCheckpoint();
     assert.done_();
   }
 })();