Add uma stats to help evaluate the impact of changes to the quota allocation logic.

Add uma stats to help evaluate the impact of changes to the quota allocation logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache" label="AppCache usage."/>
  <suffix name="DiskCache.CacheStorage" label="CacheStorage usage."/>
  <suffix name="DiskCache.ServiceWorker"
      label="ServiceWorker scriptcache usage."/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb usage."/>
  <suffix name="LevelDBEnv.IDB" label="IndexedDB usage."/>
  <suffix name="LevelDBEnv.ServiceWorker"
      label="ServiceWorker database usage."/>
  <suffix name="MojoLevelDBEnv" label="Mojo leveldb component usage."/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758
Review-Url: https://codereview.chromium.org/2858133002
Cr-Commit-Position: refs/heads/master@{#473752}
Committed: https://chromium.googlesource.com/chromium/src/+/93ccede540fea5eab25f65c15bc284a5c2c2dfbf

[michaeln, 2017-05-03 22:59:38]

Description was changed from

==========
Add uma stats to help evaluate the implact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDB.IDB corresponds to IndexedDB. Some other leveldb
consumers are
also instrumented.

BUG=605758
==========

to

==========
Add uma stats to help evaluate the implact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDB.IDB corresponds to IndexedDB. Some other leveldb
consumers are
also instrumented.

BUG=605758
==========

[michaeln, 2017-05-03 22:59:39]

michaeln@chromium.org changed reviewers:
+ jsbell@chromium.org

[michaeln, 2017-05-03 23:51:57]

Description was changed from

==========
Add uma stats to help evaluate the implact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDB.IDB corresponds to IndexedDB. Some other leveldb
consumers are
also instrumented.

BUG=605758
==========

to

==========
Add uma stats to help evaluate the implact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers are also instrumented, for example LevelDBEnv.ServiceWorker, but not
all of them are differentiated
from one another, they are logged as LevelDBEnv, and some aren't instrumented at
all.

BUG=605758
==========

[michaeln, 2017-05-03 23:52:10]

Description was changed from

==========
Add uma stats to help evaluate the implact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers are also instrumented, for example LevelDBEnv.ServiceWorker, but not
all of them are differentiated
from one another, they are logged as LevelDBEnv, and some aren't instrumented at
all.

BUG=605758
==========

to

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers are also instrumented, for example LevelDBEnv.ServiceWorker, but not
all of them are differentiated
from one another, they are logged as LevelDBEnv, and some aren't instrumented at
all.

BUG=605758
==========

[michaeln, 2017-05-03 23:53:24]

Description was changed from

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a fairly low level for some of the
storage apis:
CacheStorage, IndexedDB, AppCache, ServiceWorkerCache, and AppCache are
instrumented.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers are also instrumented, for example LevelDBEnv.ServiceWorker, but not
all of them are differentiated
from one another, they are logged as LevelDBEnv, and some aren't instrumented at
all.

BUG=605758
==========

to

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

BUG=605758
==========

[michaeln, 2017-05-04 00:01:12]

The CQ bit was checked by michaeln@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-04 00:01:37]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[michaeln, 2017-05-04 00:04:21]

ptal, i'm adding the histogram.xml changes now

[michaeln, 2017-05-04 00:45:18]

The CQ bit was checked by michaeln@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-04 00:45:49]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[michaeln, 2017-05-04 01:19:05]

Description was changed from

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

BUG=605758
==========

to

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache"/>
  <suffix name="DiskCache.CacheStorage"/>
  <suffix name="DiskCache.ServiceWorker"/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb use."/>
  <suffix name="LevelDBEnv.IDB"/>
  <suffix name="LevelDBEnv.ServiceWorker"/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758
==========

[commit-bot: I haz the power, 2017-05-04 02:34:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-04 02:34:10]

Dry run: This issue passed the CQ dry run.

[jsbell, 2017-05-04 19:40:46]

lgtm

[jsbell, 2017-05-04 19:43:37]

https://codereview.chromium.org/2858133002/diff/40001/storage/common/storage_...
File storage/common/storage_histograms.cc (right):

https://codereview.chromium.org/2858133002/diff/40001/storage/common/storage_...
storage/common/storage_histograms.cc:15: const int kMax = 10000000;
Hrm, actually... does this mean the histogram maxes out at 10GB read?

Since this is recorded for the lifetime of the Chrome process, that actually
seems like it might be a bit low. I suppose we'll find out?

[jsbell, 2017-05-04 19:48:00]

https://codereview.chromium.org/2858133002/diff/40001/storage/common/storage_...
File storage/common/storage_histograms.cc (right):

https://codereview.chromium.org/2858133002/diff/40001/storage/common/storage_...
storage/common/storage_histograms.cc:15: const int kMax = 10000000;
On 2017/05/04 19:43:37, jsbell wrote:
> Hrm, actually... does this mean the histogram maxes out at 10GB read?
> 
> Since this is recorded for the lifetime of the Chrome process, that actually
> seems like it might be a bit low. I suppose we'll find out?

Never mind, it's per-operation. That should be plenty. :)

It does mean interpreting it will require caution, e.g. 100 reads of 1k and 50
writes of 2k would be a 1:1 ratio but might show up as 2:1 depending on the
bucketing.

[michaeln, 2017-05-18 19:26:17]

michaeln@chromium.org changed reviewers:
+ isherman@chromium.org

[michaeln, 2017-05-18 19:27:17]

@isherman, ptal

[Ilya Sherman, 2017-05-19 00:17:14]

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
File storage/common/storage_histograms.cc (right):

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
storage/common/storage_histograms.cc:19:
base::Histogram::kUmaTargetedHistogramFlag);
nit: Could you use base::UmaHistogramCustomCounts here?

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
storage/common/storage_histograms.cc:26: name.append(label);
Optional nit: It might be cleaner to pass the label as a string, and write

std::string name = "Storage.BytesWritten." + label;

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:71862: +<histogram
name="Storage.BytesRead" units="bytes">
nit: I think you never emit to this histogram without a suffix -- is that
correct?  If so, please add the attribute base="true".  (Ditto for
BytesWritten.)

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:92548: +  <suffix
name="DiskCache.ServiceWorker"/>
nit: Please add a (brief) label for each suffix.

[michaeln, 2017-05-19 01:22:06]

ptal

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
File storage/common/storage_histograms.cc (right):

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
storage/common/storage_histograms.cc:19:
base::Histogram::kUmaTargetedHistogramFlag);
On 2017/05/19 00:17:14, Ilya Sherman wrote:
> nit: Could you use base::UmaHistogramCustomCounts here?

yes, thats much better, thank you :)

https://codereview.chromium.org/2858133002/diff/60001/storage/common/storage_...
storage/common/storage_histograms.cc:26: name.append(label);
On 2017/05/19 00:17:14, Ilya Sherman wrote:
> Optional nit: It might be cleaner to pass the label as a string, and write
> 
> std::string name = "Storage.BytesWritten." + label;

i'd rather not have to construct a string at each callsite, i've cleaned it up a
little for readability

void RecordBytesRead(const char* label, int amount) {
  const std::string name = "Storage.BytesRead.";
  base::UmaHistogramCounts10M(name + label, amount);
}

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:71862: +<histogram
name="Storage.BytesRead" units="bytes">
On 2017/05/19 00:17:14, Ilya Sherman wrote:
> nit: I think you never emit to this histogram without a suffix -- is that
> correct?  If so, please add the attribute base="true".  (Ditto for
> BytesWritten.)

Done.

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:92548: +  <suffix
name="DiskCache.ServiceWorker"/>
On 2017/05/19 00:17:14, Ilya Sherman wrote:
> nit: Please add a (brief) label for each suffix.

i think it's self explanatory, no?

[Ilya Sherman, 2017-05-19 06:24:46]

LGTM % labels.  Thanks.

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/2858133002/diff/60001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:92548: +  <suffix
name="DiskCache.ServiceWorker"/>
On 2017/05/19 01:22:05, michaeln wrote:
> On 2017/05/19 00:17:14, Ilya Sherman wrote:
> > nit: Please add a (brief) label for each suffix.
> 
> i think it's self explanatory, no?

It is, but it's still nice to include a brief label -- if nothing else, to
reassure the reader that it's exactly as straightforward as expected.

[michaeln, 2017-05-19 19:26:24]

The CQ bit was checked by michaeln@chromium.org

[michaeln, 2017-05-19 19:26:24]

The patchset sent to the CQ was uploaded after l-g-t-m from jsbell@chromium.org,
isherman@chromium.org
Link to the patchset: https://codereview.chromium.org/2858133002/#ps100001
(title: "labels")

[commit-bot: I haz the power, 2017-05-19 19:27:38]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-19 19:39:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-19 19:39:50]

Try jobs failed on following builders:
  cast_shell_linux on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_linu...)
  linux_chromium_tsan_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[michaeln, 2017-05-19 21:08:21]

Description was changed from

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache"/>
  <suffix name="DiskCache.CacheStorage"/>
  <suffix name="DiskCache.ServiceWorker"/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb use."/>
  <suffix name="LevelDBEnv.IDB"/>
  <suffix name="LevelDBEnv.ServiceWorker"/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758
==========

to

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache" label="AppCache usage."/>
  <suffix name="DiskCache.CacheStorage" label="CacheStorage usage."/>
  <suffix name="DiskCache.ServiceWorker"
      label="ServiceWorker scriptcache usage."/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb usage."/>
  <suffix name="LevelDBEnv.IDB" label="IndexedDB usage."/>
  <suffix name="LevelDBEnv.ServiceWorker"
      label="ServiceWorker database usage."/>
  <suffix name="MojoLevelDBEnv" label="Mojo leveldb component usage."/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758
==========

[michaeln, 2017-05-19 21:08:21]

michaeln@chromium.org changed reviewers:
+ mek@chromium.org

[michaeln, 2017-05-19 21:09:05]

@mek, ptal at env_mojo.cc and h

[michaeln, 2017-05-19 21:13:31]

The CQ bit was checked by michaeln@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-19 21:14:36]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Marijn Kruisselbrink, 2017-05-19 21:28:28]

lgtm

https://codereview.chromium.org/2858133002/diff/80002/components/leveldb/env_...
File components/leveldb/env_mojo.cc (right):

https://codereview.chromium.org/2858133002/diff/80002/components/leveldb/env_...
components/leveldb/env_mojo.cc:460:
base::UmaHistogramCounts10M("Storage.BytesRead.MojoLevelDBEnv", amount);
nit: since these histogram names are (currently) always static you could just
use the macro version rather than the function version

[michaeln, 2017-05-19 21:37:55]

thnx!

https://codereview.chromium.org/2858133002/diff/80002/components/leveldb/env_...
File components/leveldb/env_mojo.cc (right):

https://codereview.chromium.org/2858133002/diff/80002/components/leveldb/env_...
components/leveldb/env_mojo.cc:460:
base::UmaHistogramCounts10M("Storage.BytesRead.MojoLevelDBEnv", amount);
On 2017/05/19 21:28:28, Marijn Kruisselbrink wrote:
> nit: since these histogram names are (currently) always static you could just
> use the macro version rather than the function version

Done.

[michaeln, 2017-05-19 22:00:01]

The CQ bit was checked by michaeln@chromium.org

[michaeln, 2017-05-19 22:00:01]

The patchset sent to the CQ was uploaded after l-g-t-m from
isherman@chromium.org, jsbell@chromium.org, mek@chromium.org
Link to the patchset: https://codereview.chromium.org/2858133002/#ps130001
(title: "macros")

[commit-bot: I haz the power, 2017-05-19 22:01:03]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-19 23:27:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-19 23:27:38]

Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[michaeln, 2017-05-19 23:43:35]

The CQ bit was checked by michaeln@chromium.org

[commit-bot: I haz the power, 2017-05-19 23:43:58]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-20 03:00:56]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-20 03:00:58]

Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[michaeln, 2017-05-22 20:45:57]

The CQ bit was checked by michaeln@chromium.org

[commit-bot: I haz the power, 2017-05-22 20:46:18]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-23 00:01:26]

CQ is committing da patch.

Bot data: {"patchset_id": 130001, "attempt_start_ts": 1495485957532170,
"parent_rev": "075c148ae5e1e965596c1456c68704c1443df3e6", "commit_rev":
"93ccede540fea5eab25f65c15bc284a5c2c2dfbf"}

[commit-bot: I haz the power, 2017-05-23 00:01:39]

Description was changed from

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache" label="AppCache usage."/>
  <suffix name="DiskCache.CacheStorage" label="CacheStorage usage."/>
  <suffix name="DiskCache.ServiceWorker"
      label="ServiceWorker scriptcache usage."/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb usage."/>
  <suffix name="LevelDBEnv.IDB" label="IndexedDB usage."/>
  <suffix name="LevelDBEnv.ServiceWorker"
      label="ServiceWorker database usage."/>
  <suffix name="MojoLevelDBEnv" label="Mojo leveldb component usage."/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758
==========

to

==========
Add uma stats to help evaluate the impact of changes to the quota allocation
logic.

This CL adds several Storage.BytesRead.XXX and Storage.BytesWritten.XXX
histograms.
The size of each read or write is logged at a low level for:
CacheStorage, IndexedDB, ServiceWorker, and AppCache.

Storage.BytesXXX.LevelDBEnv.IDB corresponds to IndexedDB. Some other leveldb
consumers
are also instrumented, for example LevelDBEnv.ServiceWorker, but not all of them
are
differentiated from one another, they are logged as LevelDBEnv, and some aren't
instrumented at all.

Here are the labels...

<histogram_suffixes name="Storage.Bytes" separator=".">
  <suffix name="DiskCache.AppCache" label="AppCache usage."/>
  <suffix name="DiskCache.CacheStorage" label="CacheStorage usage."/>
  <suffix name="DiskCache.ServiceWorker"
      label="ServiceWorker scriptcache usage."/>
  <suffix name="LevelDBEnv" label="Undifferentiated leveldb usage."/>
  <suffix name="LevelDBEnv.IDB" label="IndexedDB usage."/>
  <suffix name="LevelDBEnv.ServiceWorker"
      label="ServiceWorker database usage."/>
  <suffix name="MojoLevelDBEnv" label="Mojo leveldb component usage."/>
  <affected-histogram name="Storage.BytesRead"/>
  <affected-histogram name="Storage.BytesWritten"/>
</histogram_suffixes>

BUG=605758

Review-Url: https://codereview.chromium.org/2858133002
Cr-Commit-Position: refs/heads/master@{#473752}
Committed:
https://chromium.googlesource.com/chromium/src/+/93ccede540fea5eab25f65c15bc2...
==========

[commit-bot: I haz the power, 2017-05-23 00:01:40]

Committed patchset #8 (id:130001) as
https://chromium.googlesource.com/chromium/src/+/93ccede540fea5eab25f65c15bc2...