diff --git a/clock_linux.cc b/clock_linux.cc
new file mode 100644
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--- /dev/null
+++ b/clock_linux.cc
@@ -0,0 +1,45 @@
+/* Copyright 2016 The Roughtime Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License. */
+
+
+#if defined(__linux)
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <time.h>
+
+namespace roughtime {
+
+// TimeUs returns the current value of the specified clock in microseconds.
+static uint64_t TimeUs(clockid_t clock) {
+  struct timespec tv;
+  if (clock_gettime(clock, &tv)) {
+    abort();
+  }
+
+  uint64_t ret = tv.tv_sec;
+  ret *= 1000000;
+  ret += tv.tv_nsec / 1000;
+  return ret;
+}
+
+// MonotonicUs returns the value of the monotonic clock in microseconds.
+uint64_t MonotonicUs() { return TimeUs(CLOCK_MONOTONIC); }
+
+// MonotonicUs returns the value of the realtime clock in microseconds.
+uint64_t RealtimeUs() { return TimeUs(CLOCK_REALTIME); }
+
+}  // namespace roughtime
+
+#endif  // __linux