add disk.device.*.latency meters

it's missing from docs and gnocchi

see: I0235087af459278b9ad0a66f95c4e4c4ac72e112

Change-Id: If2bad05c52c636c728c95ab6e9520cb6467a99e1

ceilometer/publisher/data/gnocchi_resources.yaml

@@ -109,6 +109,8 @@ resources:
       - 'disk.device.write.bytes'
       - 'disk.device.write.bytes.rate'
       - 'disk.device.latency'
+      - 'disk.device.read.latency'
+      - 'disk.device.write.latency'
       - 'disk.device.iops'
       - 'disk.device.capacity'
       - 'disk.device.allocation'

doc/source/admin/telemetry-measurements.rst

@@ -331,6 +331,16 @@ The following meters are collected for OpenStack Compute.
 |           | ative | MB   | instance | Pollster | Libvirt | Memory swap out  |
 | swap.out  |       |      | ID       |          |         |                  |
 +-----------+-------+------+----------+----------+---------+------------------+
+| **Meters added in the Queens release**                                      |
++-----------+-------+------+----------+----------+---------+------------------+
+| disk.devi\| Cumul\|      |          |          |         | Total time read  |
+| ce.read.l\| ative | ns   | Disk ID  | Pollster | Libvirt | operations have  |
+| atency    |       |      |          |          |         | taken            |
++-----------+-------+------+----------+----------+---------+------------------+
+| disk.devi\| Cumul\|      |          |          |         | Total time write |
+| ce.write.\| ative | ns   | Disk ID  | Pollster | Libvirt | operations have  |
+| latency   |       |      |          |          |         | taken            |
++-----------+-------+------+----------+----------+---------+------------------+
 
 .. note::
 

releasenotes/notes/add-disk-latency-metrics-9e5c05108a78c3d9.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Add `disk.device.read.latency` and `disk.device.write.latency` meters to
+    capture total time used by read or write operations.