tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 5c8ba98eaa4111d7a69aacb742a3bd4df9a57499..130bf86cec0adf5a7be2c43c53a68b8ee2bbbba8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -14948,17 +14948,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="Network.Shill.Cellular.DHCPOptionFailureDetected"
-    enum="NetworkDHCPOptionFailure">
-  <owner>quiche@chromium.org</owner>
-  <summary>
-    Chrome OS network metric that tracks the number of DHCP option failures
-    encountered by Shill.  This indicates that Shill is using minimal DHCP
-    options due to suspected MTU issues on the return path from the DHCP server
-    back to the client.
-  </summary>
-</histogram>

[Ilya Sherman, 2014/05/13 01:28:14]

Please mark the old histogram as deprecated, rather than deleteting it.  Ditto
for the other old histograms.

[zqiu1, 2014/05/14 17:29:53]

Done.

[zqiu1, 2014/05/14 17:29:53]

Done.

-
 <histogram name="Network.Shill.Cellular.Disconnect"
     enum="NetworkDisconnectType">
   <owner>quiche@chromium.org</owner>
@@ -15111,14 +15100,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="Network.Shill.Ethernet.DHCPOptionFailureDetected"
-    enum="NetworkDHCPOptionFailure">
-  <owner>quiche@chromium.org</owner>
+<histogram name="Network.Shill.DHCPOptionFailureDetected"
+    enum="NetworkTechnology">
+  <owner>zqiu@chromium.org</owner>
   <summary>
     Chrome OS network metric that tracks the number of DHCP option failures
-    encountered by Shill.  This indicates that Shill is using minimal DHCP
-    options due to suspected MTU issues on the return path from the DHCP server
-    back to the client.
+    encountered by Shill for each network technology.  This indicates that Shill
+    is using minimal DHCP options due to suspected MTU issues on the return path
+    from the DHCP server back to the client.
   </summary>
 </histogram>
 
@@ -15326,6 +15315,13 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Network.Shill.UserInitiatedEvents" enum="UserInitiatedEvent">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network metric that tracks the number of user-initiated events.
+  </summary>
+</histogram>

[Ilya Sherman, 2014/05/13 01:28:14]

Histograms with just a single bucket are rarely a good design.  It's very hard
to understand whether a raw number like "10,000" is "a lot" or "barely anything"
in context.  That depends on how often you expect these events, which in turn
depends on a bunch of varying factors like the number of users, the news cycle,
etc.  It's generally best to build in a baseline, so that you can understand the
metric as a relative number, i.e. a percentage.  Is there a baseline that you
could add to this histogram to make the data easier to interpret?

[zqiu1, 2014/05/14 17:29:53]

For this histogram, I don't think there is a good baseline, we'll use the other
histograms to interpret the result. And this histogram will be expanded in the
future to include other events (more buckets).
On 2014/05/13 01:28:14, Ilya Sherman wrote:

+
 <histogram name="Network.Shill.Vpn.Driver" enum="VPNDriver">
   <owner>quiche@chromium.org</owner>
   <summary>
@@ -15445,17 +15441,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="Network.Shill.Wifi.DHCPOptionFailureDetected"
-    enum="NetworkDHCPOptionFailure">
-  <owner>quiche@chromium.org</owner>
-  <summary>
-    Chrome OS network metric that tracks the number of DHCP option failures
-    encountered by Shill.  This indicates that Shill is using minimal DHCP
-    options due to suspected MTU issues on the return path from the DHCP server
-    back to the client.
-  </summary>
-</histogram>
-
 <histogram name="Network.Shill.Wifi.Disconnect" enum="NetworkDisconnectType">
   <owner>quiche@chromium.org</owner>
   <summary>
@@ -15700,14 +15685,20 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="Network.Shill.WiMax.DHCPOptionFailureDetected"
-    enum="NetworkDHCPOptionFailure">
-  <owner>quiche@chromium.org</owner>
+<histogram name="Network.Shill.WiFi.TransmitBitrateMbps" units="Mbps">
+  <owner>zqiu@chromium.org</owner>
   <summary>
-    Chrome OS network metric that tracks the number of DHCP option failures
-    encountered by Shill.  This indicates that Shill is using minimal DHCP
-    options due to suspected MTU issues on the return path from the DHCP server
-    back to the client.
+    Chrome OS network performance metric sampling the transmit bitrate in Mbps
+    for the wifi device when it is connected to a network.

[Ilya Sherman, 2014/05/13 01:28:14]

How often is it sampled / when is this histogram emitted to?

[zqiu1, 2014/05/14 17:29:53]

The transmit bitrate histogram is sampled/reported once a minute when the wifi
device is connected to a network.
On 2014/05/13 01:28:14, Ilya Sherman wrote:

+  </summary>
+</histogram>
+
+<histogram name="Network.Shill.WiFi.UserInitiatedConnectionResult"
+    enum="ConnectionResult">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network performance metric sampling the result of user-initiated
+    wifi connection attempts.

[Ilya Sherman, 2014/05/13 01:28:14]

Your use of "sampling" makes me wonder whether this is recorded on every
user-initiated wifi connection attempt, or just on a subset.

[zqiu1, 2014/05/14 17:29:53]

Sorry, bad wording. This histogram will report the result of every
user-initiated wifi connection attempt. I will update it.
On 2014/05/13 01:28:14, Ilya Sherman wrote:

   </summary>
 </histogram>
 
@@ -31721,6 +31712,12 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="GPU compositor"/>
 </enum>
 
+<enum name="ConnectionResult" type="int">
+  <int value="0" label="Success"/>
+  <int value="1" label="Failure"/>
+  <int value="2" label="Aborted"/>
+</enum>
+
 <enum name="ConnectionType" type="int">
   <summary>
     Connection type as defined in net/base/connection_type_histograms.h
@@ -38001,10 +37998,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="0" label="Corrupted Profile"/>
 </enum>
 
-<enum name="NetworkDHCPOptionFailure" type="int">
-  <int value="0" label="DHCP Option Failure"/>
-</enum>
-
 <enum name="NetworkDisconnectType" type="int">
   <int value="0" label="System Disconnect"/>
   <int value="1" label="User Disconnect"/>
@@ -38082,6 +38075,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="14" label="HTTP_GET_FAILED"/>
 </enum>
 
+<enum name="NetworkTechnology" type="int">
+  <int value="0" label="Cellular"/>
+  <int value="1" label="Ethernet"/>
+  <int value="2" label="Ethernet EAP"/>
+  <int value="3" label="WiFi"/>
+  <int value="4" label="WiMax"/>
+  <int value="5" label="VPN"/>
+  <int value="6" label="Unknown"/>

[Ilya Sherman, 2014/05/13 01:28:14]

It's unfortunate that you've chosen the last bucket to map to unknown, as it
makes it hard to extend the histogram in the future.  Well, not hard, exactly,
but slightly odd -- the "unknown" bucket ends up somewhere in the middle.  For
future reference, the best practice is always to have "Unknown" come first.

[zqiu1, 2014/05/14 17:29:53]

Thanks for the tip, I will do that in the future.
On 2014/05/13 01:28:14, Ilya Sherman wrote:

[zqiu1, 2014/05/14 17:29:53]

Thanks for the tip, I will do that next time.
On 2014/05/13 01:28:14, Ilya Sherman wrote:

+</enum>
+
 <enum name="NewTabPageActionAndroid" type="int">
   <int value="0" label="Searched using the omnibox"/>
   <int value="1" label="Navigated to Google search homepage using the omnibox"/>
@@ -42400,6 +42403,10 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="10" label="kFileSystemScheme"/>
 </enum>
 
+<enum name="UserInitiatedEvent" type="int">
+  <int value="0" label="WiFi Scan"/>
+</enum>
+
 <enum name="UserSelectableSyncType" type="int">
   <int value="0" label="Bookmarks"/>
   <int value="1" label="Preferences"/>