tools/metrics/histograms/metadata/simple/histograms.xml - cobalt - Git at Google

 <!--
 Copyright 2020 The Chromium Authors
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->

 <!--
 This file is used to generate a comprehensive list of Simple histograms
 along with a detailed description for each histogram.

 For best practices on writing histogram descriptions, see
 https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

 Please follow the instructions in the OWNERS file in this directory to find a
 reviewer. If no OWNERS file exists, please consider signing up at
 go/reviewing-metrics (Googlers only), as all subdirectories are expected to
 have an OWNERS file. As a last resort you can send the CL to
 chromium-metrics-reviews@google.com.
 -->

 <histogram-configuration>

 <histograms>

 <histogram base="true" name="SimpleCache.CacheSizeOnInit" units="KB"
     expires_after="2023-07-01">
   <owner>jkarlin@chromium.org</owner>
   <owner>shivanisha@chromium.org</owner>
   <summary>
     The size of the cache at the time that the index has finished initializing.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.ConsistencyResult"
     enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     Record the outcome of the simple DiskCache consistency check. The
     consistency check is executed every time a simple DiskCache is initialized.
     This check includes both inspecting the schema on disk and upgrading the
     schema to the latest version if necessary.
   </summary>
 </histogram>

 <histogram base="true"
     name="SimpleCache.ConsistencyResultAfterIndexFilesDeleted"
     enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     Record the final consistency check value after index files have been deleted
     from an empty simple DiskCache. This histogram will tell us how often the
     index deletion code results in a functioning cache. It will also tell us
     what kind of consistency failures cannot be recovered due to index file
     deletion.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.CreationToIndex" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time from the creation of the simple cache backend until the index has
     been loaded from disk.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.CreationToIndexFail" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time from the creation of the simple cache backend until the index fails
     to load.
   </summary>
 </histogram>

 <histogram base="true"
     name="SimpleCache.DidDeleteIndexFilesAfterFailedConsistency" enum="Boolean"
     expires_after="2023-12-08">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     Record if any simple DiskCache index files were deleted from an otherwise
     empty cache after the cache failed the initialization consistency check.
     This histogram will tell us how often the deletion code is triggering and
     modifying the disk.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.DiskCloseLatency" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time to close (write out footers and close the file) the cache entry on
     disk. Includes only successful operations.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.DiskCreateLatency" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time to access (open for creation and write initial headers) the cache
     entry on disk. Includes only successful operations.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.DiskDoomLatency" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time to remove the cache entry on disk. Includes only individually
     doomed entries, not entries bulk-erased during eviction.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.DiskOpenLatency" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time to access (open and read headers from all files) the cache entry on
     disk. Includes only successful operations.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.DiskWriteLatency" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time to write a chunk to the cache entry on disk. Includes only
     successful operations.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.EntryCreationTime" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The time, in ms, spent creating a new entry on disk. This measures time from
     when the method got removed from SimpleEntryImpl's operation queue till when
     the callback is about to be invoked, and includes all Open and Create
     operations, despite what the name may suggest.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.Eviction.EntryCount" units="units"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>The number of entries to be erased in an eviction.</summary>
 </histogram>

 <histogram base="true" name="SimpleCache.Eviction.TimeToDone" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>Time spent completing an eviction.</summary>
 </histogram>

 <histogram base="true" name="SimpleCache.Eviction.TimeToSelectEntries"
     units="ms" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>Time spent selecting entries for eviction.</summary>
 </histogram>

 <histogram name="SimpleCache.FileDescriptorLimiterAction"
     enum="SimpleCache.FileDescriptorLimiterOp" expires_after="2022-11-13">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     This even is emitted when SimpleCache is forced to either close some files
     due to being over FD limit, or reopen files it had to close due to such
     limit earlier.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.HeaderSize" units="bytes"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The size of the header stream of a Simple Cache entry, emitted every time
     the headers are written or rewritten.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.IndexCreatedEntryCount" units="units"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>The number of entries in a newly created index file.</summary>
 </histogram>

 <histogram base="true" name="SimpleCache.IndexFileStateOnLoad"
     enum="SimpleIndexState" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The state the index file is at when an attempt is made to load from it.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.IndexInitializeMethod"
     enum="SimpleCacheIndexInitializeMethod" expires_after="2023-07-01">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>The method used to initialize the simple cache index.</summary>
 </histogram>

 <histogram base="true" name="SimpleCache.IndexNumEntriesOnInit" units="entries"
     expires_after="2023-07-01">
   <owner>jkarlin@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     The number of entries in the index at the time that the index has finished
     initializing.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.IndexRestoreTime" units="ms"
     expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     Time (as measured on the worker pool) spent restoring the index file by
     iterating directory entries.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.MaxCacheSizeOnInit" units="KB"
     expires_after="2023-07-01">
   <owner>jkarlin@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     The maximum allowed size of the cache at the time that the index has
     finished initializing.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.OpenEntryIndexState"
     enum="SimpleCacheOpenEntryIndexState" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     At the time that an entry is opened, the state of that entry in the index.
   </summary>
 </histogram>

 <histogram base="true"
     name="SimpleCache.OriginalConsistencyResultBeforeSuccessfulRetry"
     enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     Record the original consistency error produced by a simple DiskCache before
     a retry was attempted and succeeded. This histogram will tell us what kind
     consistency errors can be recovered from in practice.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.RetryConsistencyResult"
     enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     Record the outcome of the simple DiskCache consistency check after retrying
     initialization on an empty cache directory. The retry may occur after
     corrupt index files were deleted from an empty cache. The retry may also
     occur if the original failed initialization left an empty directory without
     any index files. This histogram will tell us how often the retry succeeds in
     recovering caches and also which consistency checks cannot be recovered.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.StaleIndexExtraEntryCount"
     units="entries" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     Count of the number of entries recorded in the index, but not actually
     present in the cache. Recorded each time a stale index is found and a
     directory rescan is required.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.StaleIndexMissedEntryCount"
     units="entries" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     Count of the number of entries present in a cache, but not recorded in the
     index. Recorded each time a stale index is found and a directory rescan is
     required.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.StaleIndexQuality"
     enum="SimpleCacheStaleIndexQuality" expires_after="2023-07-01">
   <owner>morlovich@chromium.org</owner>
   <owner>wanderview@chromium.org</owner>
   <summary>
     The quality of a &quot;stale&quot; index compared to a full directory
     rescan. Recorded immediately after every directory scan for stale indexes.
   </summary>
 </histogram>

 <histogram base="true" name="SimpleCache.SyncOpenPrefetchMode"
     enum="SimpleCachePrefetchMode" expires_after="2023-12-10">
   <owner>wanderview@chromium.org</owner>
   <owner>morlovich@chromium.org</owner>
   <summary>
     The kind of prefetching performed, if any, when executing
     SimpleSynchronousEntry::ReadAndValidateStream0AndMaybe1().
   </summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.Event"
     enum="SimpleGeolocationRequestEvent" expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>Events in reqests processing of IP-based SimpleGeolocation.</summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.HasCellTowers"
     enum="SimpleGeolocationRequestHasCellTowers" expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <owner>skylarc@chromium.org</owner>
   <summary>
     This boolean histogram counts SimpleGeolocationRequests carrying a nonzero
     number of cell towers.
   </summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.HasWiFiAccessPoints"
     enum="SimpleGeolocationRequestHasWiFiAccessPoints" expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>
     This boolean histogram counts SimpleGeolocationRequests carrying nonzero
     number of WiFi access points.
   </summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.ResponseCode"
     enum="HttpResponseCode" expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>Http response codes in IP-based SimpleGeolocation.</summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.ResponseFailureTime" units="ms"
     expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>
     The time elapsed between the sending of the first API request and the time
     the final (failed) response was recorded. Includes all retries.
   </summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.ResponseSuccessTime" units="ms"
     expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>
     The time elapsed between the sending of the first API request and the time
     the final (successfull) response was recorded. Includes all retries.
   </summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.Result"
     enum="SimpleGeolocationRequestResult" expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>Result of SimpleGeolocationRequest.</summary>
 </histogram>

 <histogram name="SimpleGeolocation.Request.Retries" units="units"
     expires_after="never">
 <!-- expires-never: This reports external location provider health status and
 should be kept until we use this API.  -->

   <owner>alemate@chromium.org</owner>
   <owner>michaelpg@chromium.org</owner>
   <summary>Number of retries until the final response was recorded.</summary>
 </histogram>

 </histograms>

 </histogram-configuration>
	<!--
	Copyright 2020 The Chromium Authors
	Use of this source code is governed by a BSD-style license that can be
	found in the LICENSE file.
	-->

	<!--
	This file is used to generate a comprehensive list of Simple histograms
	along with a detailed description for each histogram.

	For best practices on writing histogram descriptions, see
	https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

	Please follow the instructions in the OWNERS file in this directory to find a
	reviewer. If no OWNERS file exists, please consider signing up at
	go/reviewing-metrics (Googlers only), as all subdirectories are expected to
	have an OWNERS file. As a last resort you can send the CL to
	chromium-metrics-reviews@google.com.
	-->

	<histogram-configuration>

	<histograms>

	<histogram base="true" name="SimpleCache.CacheSizeOnInit" units="KB"
	expires_after="2023-07-01">
	<owner>jkarlin@chromium.org</owner>
	<owner>shivanisha@chromium.org</owner>
	<summary>
	The size of the cache at the time that the index has finished initializing.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.ConsistencyResult"
	enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	Record the outcome of the simple DiskCache consistency check. The
	consistency check is executed every time a simple DiskCache is initialized.
	This check includes both inspecting the schema on disk and upgrading the
	schema to the latest version if necessary.
	</summary>
	</histogram>

	<histogram base="true"
	name="SimpleCache.ConsistencyResultAfterIndexFilesDeleted"
	enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	Record the final consistency check value after index files have been deleted
	from an empty simple DiskCache. This histogram will tell us how often the
	index deletion code results in a functioning cache. It will also tell us
	what kind of consistency failures cannot be recovered due to index file
	deletion.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.CreationToIndex" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time from the creation of the simple cache backend until the index has
	been loaded from disk.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.CreationToIndexFail" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time from the creation of the simple cache backend until the index fails
	to load.
	</summary>
	</histogram>

	<histogram base="true"
	name="SimpleCache.DidDeleteIndexFilesAfterFailedConsistency" enum="Boolean"
	expires_after="2023-12-08">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	Record if any simple DiskCache index files were deleted from an otherwise
	empty cache after the cache failed the initialization consistency check.
	This histogram will tell us how often the deletion code is triggering and
	modifying the disk.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.DiskCloseLatency" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time to close (write out footers and close the file) the cache entry on
	disk. Includes only successful operations.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.DiskCreateLatency" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time to access (open for creation and write initial headers) the cache
	entry on disk. Includes only successful operations.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.DiskDoomLatency" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time to remove the cache entry on disk. Includes only individually
	doomed entries, not entries bulk-erased during eviction.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.DiskOpenLatency" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time to access (open and read headers from all files) the cache entry on
	disk. Includes only successful operations.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.DiskWriteLatency" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time to write a chunk to the cache entry on disk. Includes only
	successful operations.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.EntryCreationTime" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The time, in ms, spent creating a new entry on disk. This measures time from
	when the method got removed from SimpleEntryImpl's operation queue till when
	the callback is about to be invoked, and includes all Open and Create
	operations, despite what the name may suggest.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.Eviction.EntryCount" units="units"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>The number of entries to be erased in an eviction.</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.Eviction.TimeToDone" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>Time spent completing an eviction.</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.Eviction.TimeToSelectEntries"
	units="ms" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>Time spent selecting entries for eviction.</summary>
	</histogram>

	<histogram name="SimpleCache.FileDescriptorLimiterAction"
	enum="SimpleCache.FileDescriptorLimiterOp" expires_after="2022-11-13">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	This even is emitted when SimpleCache is forced to either close some files
	due to being over FD limit, or reopen files it had to close due to such
	limit earlier.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.HeaderSize" units="bytes"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The size of the header stream of a Simple Cache entry, emitted every time
	the headers are written or rewritten.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.IndexCreatedEntryCount" units="units"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>The number of entries in a newly created index file.</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.IndexFileStateOnLoad"
	enum="SimpleIndexState" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The state the index file is at when an attempt is made to load from it.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.IndexInitializeMethod"
	enum="SimpleCacheIndexInitializeMethod" expires_after="2023-07-01">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>The method used to initialize the simple cache index.</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.IndexNumEntriesOnInit" units="entries"
	expires_after="2023-07-01">
	<owner>jkarlin@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	The number of entries in the index at the time that the index has finished
	initializing.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.IndexRestoreTime" units="ms"
	expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	Time (as measured on the worker pool) spent restoring the index file by
	iterating directory entries.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.MaxCacheSizeOnInit" units="KB"
	expires_after="2023-07-01">
	<owner>jkarlin@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	The maximum allowed size of the cache at the time that the index has
	finished initializing.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.OpenEntryIndexState"
	enum="SimpleCacheOpenEntryIndexState" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	At the time that an entry is opened, the state of that entry in the index.
	</summary>
	</histogram>

	<histogram base="true"
	name="SimpleCache.OriginalConsistencyResultBeforeSuccessfulRetry"
	enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	Record the original consistency error produced by a simple DiskCache before
	a retry was attempted and succeeded. This histogram will tell us what kind
	consistency errors can be recovered from in practice.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.RetryConsistencyResult"
	enum="SimpleCacheConsistencyResult" expires_after="2023-06-08">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	Record the outcome of the simple DiskCache consistency check after retrying
	initialization on an empty cache directory. The retry may occur after
	corrupt index files were deleted from an empty cache. The retry may also
	occur if the original failed initialization left an empty directory without
	any index files. This histogram will tell us how often the retry succeeds in
	recovering caches and also which consistency checks cannot be recovered.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.StaleIndexExtraEntryCount"
	units="entries" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	Count of the number of entries recorded in the index, but not actually
	present in the cache. Recorded each time a stale index is found and a
	directory rescan is required.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.StaleIndexMissedEntryCount"
	units="entries" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	Count of the number of entries present in a cache, but not recorded in the
	index. Recorded each time a stale index is found and a directory rescan is
	required.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.StaleIndexQuality"
	enum="SimpleCacheStaleIndexQuality" expires_after="2023-07-01">
	<owner>morlovich@chromium.org</owner>
	<owner>wanderview@chromium.org</owner>
	<summary>
	The quality of a "stale" index compared to a full directory
	rescan. Recorded immediately after every directory scan for stale indexes.
	</summary>
	</histogram>

	<histogram base="true" name="SimpleCache.SyncOpenPrefetchMode"
	enum="SimpleCachePrefetchMode" expires_after="2023-12-10">
	<owner>wanderview@chromium.org</owner>
	<owner>morlovich@chromium.org</owner>
	<summary>
	The kind of prefetching performed, if any, when executing
	SimpleSynchronousEntry::ReadAndValidateStream0AndMaybe1().
	</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.Event"
	enum="SimpleGeolocationRequestEvent" expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>Events in reqests processing of IP-based SimpleGeolocation.</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.HasCellTowers"
	enum="SimpleGeolocationRequestHasCellTowers" expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<owner>skylarc@chromium.org</owner>
	<summary>
	This boolean histogram counts SimpleGeolocationRequests carrying a nonzero
	number of cell towers.
	</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.HasWiFiAccessPoints"
	enum="SimpleGeolocationRequestHasWiFiAccessPoints" expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>
	This boolean histogram counts SimpleGeolocationRequests carrying nonzero
	number of WiFi access points.
	</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.ResponseCode"
	enum="HttpResponseCode" expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>Http response codes in IP-based SimpleGeolocation.</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.ResponseFailureTime" units="ms"
	expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>
	The time elapsed between the sending of the first API request and the time
	the final (failed) response was recorded. Includes all retries.
	</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.ResponseSuccessTime" units="ms"
	expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>
	The time elapsed between the sending of the first API request and the time
	the final (successfull) response was recorded. Includes all retries.
	</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.Result"
	enum="SimpleGeolocationRequestResult" expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>Result of SimpleGeolocationRequest.</summary>
	</histogram>

	<histogram name="SimpleGeolocation.Request.Retries" units="units"
	expires_after="never">
	<!-- expires-never: This reports external location provider health status and
	should be kept until we use this API. -->

	<owner>alemate@chromium.org</owner>
	<owner>michaelpg@chromium.org</owner>
	<summary>Number of retries until the final response was recorded.</summary>
	</histogram>

	</histograms>

	</histogram-configuration>