Add support for AMD Excavator Microarchitecture

Currently the Microarchitecture table in cpu_identity only supports Intel
Microarchitectures.  Add an entry for the AMD Excavator microarchitecture.

BUG=b:69376360
TEST=unit_tests --gtest_filter="CpuIdentityTest.*"
R=chongjiang@chromium.org,sque@chromium.org

Change-Id: I255596e330e0353ab4bec2d51ea25d2420cbcb30
Reviewed-on: https://chromium-review.googlesource.com/1033457Reviewed-by: Simon Que <sque@chromium.org>
Commit-Queue: Daniel Kurtz <djkurtz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555469}

chrome/browser/metrics/perf/cpu_identity.cc

@@ -59,6 +59,7 @@ const CpuUarchTableEntry kCpuUarchTable[] = {
     {"0F_03", "Prescott"},
     {"0F_04", "Prescott"},
     {"0F_06", "Presler"},
+    {"0F_70", "Excavator"},   // AMD Stoney Ridge
 };
 
 const CpuUarchTableEntry* kCpuUarchTableEnd =
@@ -78,8 +79,8 @@ CPUIdentity::CPUIdentity(const CPUIdentity& other) = default;
 CPUIdentity::~CPUIdentity() {}
 
 std::string GetCpuUarch(const CPUIdentity& cpuid) {
-  if (cpuid.vendor != "GenuineIntel")
-    return std::string();  // Non-Intel
+  if (cpuid.vendor != "GenuineIntel" && cpuid.vendor != "AuthenticAMD")
+    return std::string();  // Non-Intel or -AMD
 
   std::string family_model =
       base::StringPrintf("%02X_%02X", cpuid.family, cpuid.model);

chrome/browser/metrics/perf/cpu_identity.h

@@ -32,8 +32,8 @@ struct CPUIdentity {
 CPUIdentity GetCPUIdentity();
 
 // Return the CPU microarchitecture based on the family and model derived
-// from |cpuid|, and kCpuUarchTable, or the empty string for non-Intel or
-// unknown microarchitectures.
+// from |cpuid|, and kCpuUarchTable, or the empty string for unknown
+// microarchitectures.
 std::string GetCpuUarch(const CPUIdentity& cpuid);
 
 // Simplify a CPU model name. The rules are:

chrome/browser/metrics/perf/cpu_identity_unittest.cc

@@ -37,6 +37,16 @@ TEST(CpuIdentityTest, DefaultCommandsBasedOnUarch_SandyBridge) {
   EXPECT_EQ("SandyBridge", GetCpuUarch(cpuid));
 }
 
+TEST(CpuIdentityTest, DefaultCommandsBasedOnUarch_Excavator) {
+  CPUIdentity cpuid;
+  cpuid.arch = "x86_64";
+  cpuid.vendor = "AuthenticAMD";
+  cpuid.family = 0x0f;
+  cpuid.model = 0x70;  // Excavator
+  cpuid.model_name = "";
+  EXPECT_EQ("Excavator", GetCpuUarch(cpuid));
+}
+
 TEST(CpuIdentityTest, DefaultCommandsBasedOnArch_x86_32) {
   CPUIdentity cpuid;
   cpuid.arch = "x86";
@@ -50,7 +60,7 @@ TEST(CpuIdentityTest, DefaultCommandsBasedOnArch_x86_32) {
 TEST(CpuIdentityTest, DefaultCommandsBasedOnArch_Unknown) {
   CPUIdentity cpuid;
   cpuid.arch = "x86_64";
-  cpuid.vendor = "NotIntel";
+  cpuid.vendor = "NotIntelOrAmd";
   cpuid.family = 0;
   cpuid.model = 0;
   cpuid.model_name = "";

chrome/browser/metrics/perf/perf_provider_chromeos.h

@@ -274,7 +274,8 @@ std::vector<RandomSelector::WeightAndValue> GetDefaultCommandsForCpu(
 // that is the narrowest match for the CPU identified by |cpuid|.
 // Valid CPU specifiers, in increasing order of specificity, are:
 // "default", a system architecture (e.g. "x86_64"), a CPU microarchitecture
-// (currently only Intel uarchs supported), or a CPU model name substring.
+// (currently only some Intel and AMD uarchs supported), or a CPU model name
+// substring.
 std::string FindBestCpuSpecifierFromParams(
     const std::map<std::string, std::string>& params,
     const CPUIdentity& cpuid);