diff --git a/benchmarks/stdlib_benchmark.cpp b/benchmarks/stdlib_benchmark.cpp
new file mode 100644
index 0000000..7a12eb6
--- /dev/null
+++ b/benchmarks/stdlib_benchmark.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include <langinfo.h>
+#include <locale.h>
+#include <stdlib.h>
+
+#include <benchmark/benchmark.h>
+#include "util.h"
+
+static void BM_stdlib_malloc_free(benchmark::State& state) {
+  const size_t nbytes = state.range(0);
+
+  void* c;
+  while (state.KeepRunning()) {
+    c = malloc(nbytes);
+    free(c);
+  }
+
+  state.SetBytesProcessed(uint64_t(state.iterations()) * uint64_t(nbytes));
+}
+BIONIC_BENCHMARK(BM_stdlib_malloc_free);
+
+static void BM_stdlib_mbstowcs(benchmark::State& state) {
+  const size_t buf_alignment = state.range(0);
+  const size_t widebuf_alignment = state.range(1);
+
+  std::vector<char> buf;
+  std::vector<wchar_t> widebuf;
+
+  setlocale(LC_CTYPE, "C.UTF-8")
+  || setlocale(LC_CTYPE, "en_US.UTF-8")
+  || setlocale(LC_CTYPE, "en_GB.UTF-8")
+  || setlocale(LC_CTYPE, "en.UTF-8")
+  || setlocale(LC_CTYPE, "de_DE-8")
+  || setlocale(LC_CTYPE, "fr_FR-8");
+  if (strcmp(nl_langinfo(CODESET), "UTF-8")) abort();
+
+  char* buf_aligned = GetAlignedPtr(&buf, buf_alignment, 500000);
+  wchar_t* widebuf_aligned = GetAlignedPtr(&widebuf, widebuf_alignment, 500000);
+  size_t i, j, k, l;
+  l = 0;
+  for (i=0xc3; i<0xe0; i++)
+    for (j=0x80; j<0xc0; j++)
+      buf[l++] = i, buf[l++] = j;
+  for (i=0xe1; i<0xed; i++)
+    for (j=0x80; j<0xc0; j++)
+      for (k=0x80; k<0xc0; k++)
+        buf[l++] = i, buf[l++] = j, buf[l++] = k;
+  for (i=0xf1; i<0xf4; i++)
+    for (j=0x80; j<0xc0; j++)
+      for (k=0x80; k<0xc0; k++)
+        buf[l++] = i, buf[l++] = j, buf[l++] = 0x80, buf[l++] = k;
+  buf[l++] = 0;
+
+  volatile size_t c __attribute__((unused)) = 0;
+  while (state.KeepRunning()) {
+    c = mbstowcs(widebuf_aligned, buf_aligned, 500000);
+  }
+
+  state.SetBytesProcessed(uint64_t(state.iterations()) * uint64_t(500000));
+}
+BIONIC_BENCHMARK(BM_stdlib_mbstowcs);
+
+static void BM_stdlib_mbrtowc(benchmark::State& state) {
+  const size_t buf_alignment = state.range(0);
+
+  std::vector<char> buf;
+
+  setlocale(LC_CTYPE, "C.UTF-8")
+  || setlocale(LC_CTYPE, "en_US.UTF-8")
+  || setlocale(LC_CTYPE, "en_GB.UTF-8")
+  || setlocale(LC_CTYPE, "en.UTF-8")
+  || setlocale(LC_CTYPE, "de_DE-8")
+  || setlocale(LC_CTYPE, "fr_FR-8");
+  if (strcmp(nl_langinfo(CODESET), "UTF-8")) abort();
+
+  char* buf_aligned = GetAlignedPtr(&buf, buf_alignment, 500000);
+  size_t i, j, k, l;
+  l = 0;
+  for (i=0xc3; i<0xe0; i++)
+    for (j=0x80; j<0xc0; j++)
+      buf[l++] = i, buf[l++] = j;
+  for (i=0xe1; i<0xed; i++)
+    for (j=0x80; j<0xc0; j++)
+      for (k=0x80; k<0xc0; k++)
+        buf[l++] = i, buf[l++] = j, buf[l++] = k;
+  for (i=0xf1; i<0xf4; i++)
+    for (j=0x80; j<0xc0; j++)
+      for (k=0x80; k<0xc0; k++)
+        buf[l++] = i, buf[l++] = j, buf[l++] = 0x80, buf[l++] = k;
+  buf[l++] = 0;
+
+  wchar_t wc = 0;
+  while (state.KeepRunning()) {
+    for (j = 0; buf_aligned[j]; j+=mbrtowc(&wc, buf_aligned + j, 4, NULL)) {
+    }
+  }
+
+  state.SetBytesProcessed(uint64_t(state.iterations()) * uint64_t(500000));
+}
+BIONIC_BENCHMARK(BM_stdlib_mbrtowc);