diff --git a/util/env_posix.cc b/util/env_posix.cc
index 98a401924..fa97b6c93 100644
--- a/util/env_posix.cc
+++ b/util/env_posix.cc
@@ -7,7 +7,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
-#include <chrono>
 #include <deque>
 #include <set>
 #include <dirent.h>
@@ -1400,13 +1399,24 @@ class PosixEnv : public Env {
   }
 
   virtual uint64_t NowMicros() override {
-    return std::chrono::duration_cast<std::chrono::microseconds>(
-        std::chrono::system_clock::now().time_since_epoch()).count();
+    struct timeval tv;
+    gettimeofday(&tv, nullptr);
+    return static_cast<uint64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
   }
 
   virtual uint64_t NowNanos() override {
-    return std::chrono::duration_cast<std::chrono::nanoseconds>(
-        std::chrono::steady_clock::now().time_since_epoch()).count();
+#ifdef OS_LINUX
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return static_cast<uint64_t>(ts.tv_sec) * 1000000000 + ts.tv_nsec;
+#elif __MACH__
+    clock_serv_t cclock;
+    mach_timespec_t ts;
+    host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
+    clock_get_time(cclock, &ts);
+    mach_port_deallocate(mach_task_self(), cclock);
+#endif
+    return static_cast<uint64_t>(ts.tv_sec) * 1000000000 + ts.tv_nsec;
   }
 
   virtual void SleepForMicroseconds(int micros) override { usleep(micros); }