Merge 688e421184 into c552ff2451

mlx/transforms.cpp

@@ -2,6 +2,7 @@
 #include <algorithm>
 #include <deque>
 #include <future>
+#include <mutex>
 #include <numeric>
 #include <set>
 #include <sstream>
@@ -36,6 +37,42 @@ class Synchronizer : public Primitive {
   DEFINE_PRINT(Synchronize);
 };
 
+class Interrupt {
+ private:
+  static std::mutex mutex_;
+  static bool eval_running_;
+  static bool interrupt_;
+
+ public:
+  Interrupt() {
+    std::unique_lock lk(mutex_);
+    eval_running_ = true;
+  }
+
+  static bool interrupt() {
+    std::unique_lock lk(mutex_);
+    if (eval_running_) {
+      interrupt_ = true;
+      return true;
+    }
+    return false;
+  }
+
+  static bool interrupted() {
+    std::unique_lock lk(mutex_);
+    return interrupt_;
+  }
+
+  ~Interrupt() {
+    std::unique_lock lk(mutex_);
+    eval_running_ = false;
+    interrupt_ = false;
+  }
+};
+std::mutex Interrupt::mutex_{};
+bool Interrupt::eval_running_ = false;
+bool Interrupt::interrupt_ = false;
+
 // Initialize the static tracing members from transforms_impl.h
 //
 // These are used to implement the in_tracing() function the returns true if we
@@ -50,6 +87,8 @@ int detail::InTracing::grad_counter{0};
 int detail::RetainGraph::tracing_counter{0};
 
 array eval_impl(std::vector<array> outputs, bool async) {
+  Interrupt interrupt;
+
   std::deque<array> tape;
 
   // Make an effort to choose a good output stream
@@ -260,6 +299,11 @@ array eval_impl(std::vector<array> outputs, bool async) {
     if (!arr.is_tracer()) {
       arr.detach();
     }
+
+    if (Interrupt::interrupted()) {
+      synchronizer.attach_event(Event{stream});
+      break;
+    }
   }
 
   // Signal the event in its stream
@@ -274,6 +318,10 @@ array eval_impl(std::vector<array> outputs, bool async) {
   return synchronizer;
 }
 
+bool interrupt_eval() {
+  return Interrupt::interrupt();
+}
+
 void async_eval(std::vector<array> outputs) {
   if (outputs.empty()) {
     return;

mlx/transforms.h

@@ -22,6 +22,14 @@ void eval(Arrays&&... outputs) {
   eval(std::vector<array>{std::forward<Arrays>(outputs)...});
 }
 
+/**
+ * Interrupt an ongoing eval.
+ *
+ * Leaves the graph in a valid state. Returns true if an ongoing eval was
+ * interrupted and false otherwise.
+ */
+bool interrupt_eval();
+
 /**
  *  Computes the output and vector-Jacobian product (VJP) of a function.
  *

tests/eval_tests.cpp

@@ -1,5 +1,4 @@
 // Copyright © 2023 Apple Inc.
-
 #include "doctest/doctest.h"
 
 #include "mlx/mlx.h"
@@ -91,3 +90,17 @@ TEST_CASE("test eval graph retention when not tracing") {
   CHECK(!a.has_primitive());
   CHECK(a.is_available());
 }
+
+TEST_CASE("test interrupt eval") {
+  auto x = zeros({1024}, int32);
+  for (int i = 0; i < 1000; ++i) {
+    x = x + 1;
+  }
+  std::thread t([x]() { eval(x); });
+  while (!interrupt_eval()) {
+  }
+  t.join();
+  // Check that x is not evaluated
+  CHECK(!x.is_available());
+  CHECK(array_equal(x, full({1024}, 1000, int32)).item<bool>());
+}