[Downloads] Deprecate incorrect metrics.

[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

Download.WriteSize:
Download.WriteLoopCount:

  WriteSize and WriteLoopCount metrics aren't actionable. WriteSize
  depends on the buffer sizes involved and the data is too noisy to be
  useful. Likewise WriteLoopCount counts the number of attempts it takes
  to fully write out a buffer. This isn't actionable.

BUG=none

Review-Url: https://codereview.chromium.org/2598773002
Cr-Commit-Position: refs/heads/master@{#441780}
Committed: https://chromium.googlesource.com/chromium/src/+/d1d21f7fcc326b5875fbe7d4ff95376c8fcddbc3

[asanka, 2016-12-21 20:03:04]

asanka@chromium.org changed reviewers:
+ asvitkine@chromium.org, dtrainor@chromium.org

[asanka, 2016-12-21 20:03:39]

asvitkine:
  /histograms/

dtrainor:
  /download/

:-)

[asanka, 2016-12-21 20:27:47]

Description was changed from

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

BUG=none
==========

to

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

BUG=none
==========

[asanka, 2016-12-21 22:00:38]

Description was changed from

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

BUG=none
==========

to

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

BUG=none
==========

[asanka, 2016-12-21 22:11:47]

Description was changed from

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

BUG=none
==========

to

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

Download.WriteSize:
Download.WriteLoopCount:

  WriteSize and WriteLoopCount metrics aren't actionable. WriteSize
  depends on the buffer sizes involved and the data is too noisy to be
  useful. Likewise WriteLoopCount counts the number of attempts it takes
  to fully write out a buffer. This isn't actionable.

BUG=none
==========

[David Trainor- moved to gerrit, 2017-01-03 19:38:19]

download/ lgtm

[Alexei Svitkine (slow), 2017-01-03 19:46:46]

lgtm

[asanka, 2017-01-05 21:50:27]

Thanks!

[asanka, 2017-01-05 21:50:52]

The CQ bit was checked by asanka@chromium.org

[commit-bot: I haz the power, 2017-01-05 21:51:27]

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, 2017-01-06 01:16:47]

CQ is committing da patch.

Bot data: {"patchset_id": 60001, "attempt_start_ts": 1483653052715950,
"parent_rev": "f4b2e47af70ac16412fc82c81db5eb16bb34f794", "commit_rev":
"d1d21f7fcc326b5875fbe7d4ff95376c8fcddbc3"}

[commit-bot: I haz the power, 2017-01-06 01:17:36]

Description was changed from

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

Download.WriteSize:
Download.WriteLoopCount:

  WriteSize and WriteLoopCount metrics aren't actionable. WriteSize
  depends on the buffer sizes involved and the data is too noisy to be
  useful. Likewise WriteLoopCount counts the number of attempts it takes
  to fully write out a buffer. This isn't actionable.

BUG=none
==========

to

==========
[Downloads] Deprecate incorrect metrics.

Download.ActualBandwidth:
Download.PotentialBandwidth:
Download.BandwidthUsed:

  These metrics were being recorded on each network read and were
  assuming that the size of the buffer and the duration between the
  prior read completion event and this one were reliable indicators of
  bandwidth.

  In practice, recording on each read is noisy and not all
  useful when aggregated across all users. Also size_of_buffer /
  elapsed_time is not an indicator of potential bandwidth, which makes
  both the PotentialBandwidth and BandwidthUsed incorrect.

Download.DiskBandwidthUsedPercentage:

  Neither useful nor correct.

SB2.DownloadDuration:

  Was measuring the lifetime of a DownloadRequestCore object, which
  doesn't correspond to the duration of a download.

Download.InterruptedOverrunBytes:
Download.InterruptedUnderrunBytes:

  When reporting UMA, the code was incorrectly picking the histogram
  name. Hence the meanings of the two histograms were switched. Rather
  than deprecating, I switched the descriptions around. The names are
  henceforth a bit odd, but the description should clarify what they are
  measuring.

Download.WriteSize:
Download.WriteLoopCount:

  WriteSize and WriteLoopCount metrics aren't actionable. WriteSize
  depends on the buffer sizes involved and the data is too noisy to be
  useful. Likewise WriteLoopCount counts the number of attempts it takes
  to fully write out a buffer. This isn't actionable.

BUG=none

Review-Url: https://codereview.chromium.org/2598773002
Cr-Commit-Position: refs/heads/master@{#441780}
Committed:
https://chromium.googlesource.com/chromium/src/+/d1d21f7fcc326b5875fbe7d4ff95...
==========

[commit-bot: I haz the power, 2017-01-06 01:17:37]

Committed patchset #4 (id:60001) as
https://chromium.googlesource.com/chromium/src/+/d1d21f7fcc326b5875fbe7d4ff95...