Linux: Add a UMA for the glibc version.

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

Index: chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
===================================================================
--- chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc	(revision 194041)
+++ chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc	(working copy)
@@ -5,6 +5,7 @@
 #include "chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.h"
 
 #include <string>
+#include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ -20,8 +21,32 @@
 #include "ui/base/touch/touch_device.h"
 #include "ui/base/ui_base_switches.h"
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+#include <gnu/libc-version.h>
+
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#endif
+
 namespace {
 
+enum UMALinuxGlibcVersion {
+  UMA_LINUX_GLIBC_NOT_PARSEABLE,
+  UMA_LINUX_GLIBC_UNKNOWN,
+  UMA_LINUX_GLIBC_2_11 = 11,

[jar (doing other things), 2013/04/14 16:14:15]

See note below about how to avoid having to list the enumerated constants values
(i.e., "= 11" etc.) here.

+  UMA_LINUX_GLIBC_2_12 = 12,
+  UMA_LINUX_GLIBC_2_13 = 13,
+  UMA_LINUX_GLIBC_2_14 = 14,
+  UMA_LINUX_GLIBC_2_15 = 15,
+  UMA_LINUX_GLIBC_2_16 = 16,
+  UMA_LINUX_GLIBC_2_17 = 17,
+  UMA_LINUX_GLIBC_2_18 = 18,
+  UMA_LINUX_GLIBC_2_19 = 19,
+  // NOTE: Add new version above this line and update the enum list in
+  // tools/histograms/histograms.xml accordingly.
+  UMA_LINUX_GLIBC_VERSION_COUNT
+};
+
 enum UMATouchEventsState {
   UMA_TOUCH_EVENTS_ENABLED,
   UMA_TOUCH_EVENTS_AUTO_ENABLED,
@@ -32,7 +57,7 @@
   UMA_TOUCH_EVENTS_STATE_COUNT
 };
 
-void LogIntelMicroArchitecture() {
+void RecordIntelMicroArchitecture() {
 #if defined(ARCH_CPU_X86_FAMILY)
   base::CPU cpu;
   base::CPU::IntelMicroArchitecture arch = cpu.GetIntelMicroArchitecture();
@@ -49,6 +74,32 @@
                             ShellIntegration::NUM_DEFAULT_STATES);
 }
 
+void RecordLinuxGlibcVersion() {
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+  std::string glibc_version_string(gnu_get_libc_version());
+  std::vector<std::string> split_glibc_version;
+  base::SplitString(glibc_version_string, '.', &split_glibc_version);
+
+  UMALinuxGlibcVersion glibc_version_result = UMA_LINUX_GLIBC_NOT_PARSEABLE;
+  unsigned glibc_major_version = 0;
+  unsigned glibc_minor_version = 0;
+  if (split_glibc_version.size() == 2 &&
+      base::StringToUint(split_glibc_version[0], &glibc_major_version) &&
+      base::StringToUint(split_glibc_version[1], &glibc_minor_version)) {
+    if (glibc_major_version == 2 &&
+        (glibc_minor_version >= 11 && glibc_minor_version <= 19)) {
+      // |glibc_minor_version| values lines up with the enum values.
+      glibc_version_result =
+          static_cast<UMALinuxGlibcVersion>(glibc_minor_version);

[jar (doing other things), 2013/04/14 16:14:15]

I think this might read better if you have the adjustment factor:

- 11 + UMA_LINUX_GLIBC_2_11;

Then you don't need mess around and specially define UMA_LINUX_GLIBC_2_11 to
match.... and you'll be set up to deal with another other ranges.  It is
generally nicer not to leave unused spots in the enumeration when going into an
enumerated histogram.

Following in this pattern.... after you verify that you have a major version of
2, you could go ahead and translate it, and then check to see that the
translation is between 
UMA_LINUX_GLIBC_2_11
UMA_LINUX_GLIBC_2_19

I think that will also make the connection with the enums a bit clearer (and
avoid having the less obvious magic constants 11 and 19 show up in code.

WDYT?

+    } else {
+      glibc_version_result = UMA_LINUX_GLIBC_UNKNOWN;
+    }
+  }
+  UMA_HISTOGRAM_ENUMERATION("Linux.GlibcVersion", glibc_version_result,
+                            UMA_LINUX_GLIBC_VERSION_COUNT);
+#endif
+}
+
 void RecordTouchEventState() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   const std::string touch_enabled_switch =
@@ -83,7 +134,7 @@
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PreProfileInit() {
-  LogIntelMicroArchitecture();
+  RecordIntelMicroArchitecture();
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PreBrowserStart() {
@@ -97,6 +148,7 @@
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PostBrowserStart() {
+  RecordLinuxGlibcVersion();
   RecordTouchEventState();
 }