diff --git a/src/developer/debug/zxdb/BUILD.gn b/src/developer/debug/zxdb/BUILD.gn
index c2b2db4..a6248e7 100644
--- a/src/developer/debug/zxdb/BUILD.gn
+++ b/src/developer/debug/zxdb/BUILD.gn
@@ -51,6 +51,19 @@
       "//third_party/googletest:gtest_main",
     ]
   }
+
+  test("zxdb_perftests") {
+    sources = [
+      "zxdb_perftests.cc",
+    ]
+
+    deps = [
+      "//src/developer/debug/zxdb/common:perf_test",
+      "//src/developer/debug/zxdb/symbols:perf_tests",
+      "//third_party/googletest:gtest",
+      "//zircon/public/lib/cmdline",
+    ]
+  }
 }
 
 install_host_tools("zxdb_host") {
diff --git a/src/developer/debug/zxdb/common/BUILD.gn b/src/developer/debug/zxdb/common/BUILD.gn
index 95def7a1..a74b30f 100644
--- a/src/developer/debug/zxdb/common/BUILD.gn
+++ b/src/developer/debug/zxdb/common/BUILD.gn
@@ -51,3 +51,22 @@
     "//third_party/googletest:gtest",
   ]
 }
+
+# Simple support library for writing perf tests. This is a much simpler variant
+# of //zircon/system/ulib/perftest that will run on the host.
+source_set("perf_test") {
+  testonly = true
+
+  sources = [
+    "perf_test.cc",
+    "perf_test.h",
+  ]
+
+  public_deps = [
+    "//third_party/googletest:gtest",
+  ]
+
+  deps = [
+    "//src/lib/fxl",
+  ]
+}
diff --git a/src/developer/debug/zxdb/common/perf_test.cc b/src/developer/debug/zxdb/common/perf_test.cc
new file mode 100644
index 0000000..75f8992
--- /dev/null
+++ b/src/developer/debug/zxdb/common/perf_test.cc
@@ -0,0 +1,90 @@
+// Copyright 2019 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/developer/debug/zxdb/common/perf_test.h"
+
+#include <stdio.h>
+
+#include "src/lib/fxl/logging.h"
+
+namespace zxdb {
+
+namespace {
+
+FILE* perf_log_file = nullptr;
+bool written_perf_line = false;
+
+}  // namespace
+
+bool InitPerfLog(const std::string& log_file) {
+  if (perf_log_file) {
+    // Trying to initialize twice.
+    FXL_NOTREACHED();
+    return false;
+  }
+
+  if (!(perf_log_file = fopen(log_file.c_str(), "w")))
+    return false;
+
+  fprintf(perf_log_file, "{\n");
+  return true;
+}
+
+void FinalizePerfLog() {
+  if (!perf_log_file) {
+    // Trying to cleanup without initializing.
+    FXL_NOTREACHED();
+    return;
+  }
+  fprintf(perf_log_file, "\n}\n");
+  fclose(perf_log_file);
+  perf_log_file = nullptr;
+}
+
+void LogPerfResult(const char* test_suite_name, const char* test_name,
+                   double value, const char* units) {
+  if (!perf_log_file) {
+    FXL_NOTREACHED();
+    return;
+  }
+
+  // Format: //zircon/system/ulib/perftest/performance-results-schema.json
+  // Example line:
+  //  {"label":"Vmo/CloneWrite/10000kbytes.close",
+  //   "test_suite":"fuchsia.zircon_benchmarks",
+  //   "unit":"nanoseconds",
+  //   "values":[2346.961749]}
+
+  // Add trailing comma for previous item when necessary.
+  if (written_perf_line)
+    fprintf(perf_log_file, ",\n");
+  written_perf_line = true;
+
+  fprintf(perf_log_file,
+          R"({"label":"%s", "test_suite":"%s", "unit":"%s", "values":[%g]})",
+          test_name, test_suite_name, units, value);
+  fflush(stdout);
+}
+
+PerfTimeLogger::PerfTimeLogger(const char* test_suite_name,
+                               const char* test_name)
+    : test_suite_name_(test_suite_name), test_name_(test_name) {
+  timer_.Start();
+}
+
+PerfTimeLogger::~PerfTimeLogger() {
+  if (!logged_)
+    Done();
+}
+
+void PerfTimeLogger::Done() {
+  // Use a floating-point millisecond value because it is more
+  // intuitive than microseconds and we want more precision than
+  // integer milliseconds
+  LogPerfResult(test_suite_name_.c_str(), test_name_.c_str(),
+                timer_.Elapsed().ToMillisecondsF(), "ms");
+  logged_ = true;
+}
+
+}  // namespace zxdb
diff --git a/src/developer/debug/zxdb/common/perf_test.h b/src/developer/debug/zxdb/common/perf_test.h
new file mode 100644
index 0000000..d9cba35
--- /dev/null
+++ b/src/developer/debug/zxdb/common/perf_test.h
@@ -0,0 +1,49 @@
+// Copyright 2019 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SRC_DEVELOPER_DEBUG_ZXDB_COMMON_PERF_TEST_H_
+#define SRC_DEVELOPER_DEBUG_ZXDB_COMMON_PERF_TEST_H_
+
+#include <string>
+
+#include "src/lib/fxl/macros.h"
+#include "src/lib/fxl/time/stopwatch.h"
+
+namespace zxdb {
+
+// Initializes and finalizes the perf log. These functions should be called at
+// the beginning and end (respectively) of running all the performance tests.
+// The init function returns true on success.
+bool InitPerfLog(const std::string& log_path);
+void FinalizePerfLog();
+
+// Writes to the perf result log the given 'value' resulting from the named
+// 'test'. The units are to aid in reading the log by people.
+void LogPerfResult(const char* test_suite_name, const char* test_name,
+                   double value, const char* units);
+
+// Automates calling LogPerfResult for the common case where you want
+// to measure the time that something took. Call Done() when the test
+// is complete if you do extra work after the test or there are stack
+// objects with potentially expensive constructors. Otherwise, this
+// class with automatically log on destruction.
+class PerfTimeLogger {
+ public:
+  PerfTimeLogger(const char* test_suite_name, const char* test_name);
+  ~PerfTimeLogger();
+
+  void Done();
+
+ private:
+  bool logged_ = false;
+  std::string test_suite_name_;
+  std::string test_name_;
+  fxl::Stopwatch timer_;
+
+  FXL_DISALLOW_COPY_AND_ASSIGN(PerfTimeLogger);
+};
+
+}  // namespace zxdb
+
+#endif  // SRC_DEVELOPER_DEBUG_ZXDB_COMMON_PERF_TEST_H_
diff --git a/src/developer/debug/zxdb/symbols/BUILD.gn b/src/developer/debug/zxdb/symbols/BUILD.gn
index eb8f1d6..54166a1 100644
--- a/src/developer/debug/zxdb/symbols/BUILD.gn
+++ b/src/developer/debug/zxdb/symbols/BUILD.gn
@@ -238,3 +238,16 @@
     test_runtime_deps = get_target_outputs(":copy_test_so")
   }
 }
+
+source_set("perf_tests") {
+  testonly = true
+
+  sources = [
+    "module_symbol_index_perftest.cc",
+  ]
+
+  deps = [
+    ":symbols",
+    "//src/developer/debug/zxdb/common:perf_test",
+  ]
+}
diff --git a/src/developer/debug/zxdb/symbols/module_symbol_index_perftest.cc b/src/developer/debug/zxdb/symbols/module_symbol_index_perftest.cc
new file mode 100644
index 0000000..67d1fa1
--- /dev/null
+++ b/src/developer/debug/zxdb/symbols/module_symbol_index_perftest.cc
@@ -0,0 +1,17 @@
+// Copyright 2019 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/developer/debug/zxdb/symbols/module_symbol_index.h"
+
+#include "gtest/gtest.h"
+#include "src/developer/debug/zxdb/common/perf_test.h"
+
+namespace zxdb {
+
+TEST(ModuleLoad, Perf) {
+  PerfTimeLogger logger("zxdb", "ModuleLoad");
+  // TODO(brettw) write this.
+}
+
+}  // namespace zxdb
diff --git a/src/developer/debug/zxdb/zxdb_perftests.cc b/src/developer/debug/zxdb/zxdb_perftests.cc
new file mode 100644
index 0000000..ae58575
--- /dev/null
+++ b/src/developer/debug/zxdb/zxdb_perftests.cc
@@ -0,0 +1,61 @@
+// Copyright 2019 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <cmdline/args_parser.h>
+
+#include "gtest/gtest.h"
+#include "src/developer/debug/zxdb/common/perf_test.h"
+
+namespace {
+
+struct CommandLineOptions {
+  std::string out_file;
+};
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  testing::InitGoogleTest(&argc, argv);
+
+  // Set up for command line parsing.
+  cmdline::ArgsParser<CommandLineOptions> parser;
+  parser.AddSwitch("out", 0,
+                   "--out\n  [required] JSON file to write perf stats to.",
+                   &CommandLineOptions::out_file);
+
+  bool requested_help = false;
+  parser.AddGeneralSwitch("help", 0, "--help\n   Print help",
+                          [&requested_help]() { requested_help = true; });
+
+  // Parse the command line.
+  CommandLineOptions options;
+  std::vector<std::string> params;
+  if (auto status = parser.Parse(argc, const_cast<const char **>(argv),
+                                 &options, &params);
+      status.has_error()) {
+    fprintf(stderr, "Error: %s\n", status.error_message().c_str());
+    return 1;
+  }
+  if (requested_help) {
+    // Gtest will have printed its own help in response to --help, and this
+    // gets appended.
+    fprintf(stderr, "\n\nPerf test options:\n\n%s\n", parser.GetHelp().c_str());
+    return 0;
+  }
+
+  // Initialize the perf test system.
+  if (options.out_file.empty()) {
+    fprintf(stderr, "Parameter --out=<output_file> is required.\n");
+    return 1;
+  }
+  if (!zxdb::InitPerfLog(options.out_file)) {
+    fprintf(stderr, "Failed to initialize perf log.\n");
+    return 1;
+  }
+
+  int result = RUN_ALL_TESTS();
+
+  zxdb::FinalizePerfLog();
+  return result;
+}