metrics: log whether drives have seek penalties (and whether this was determined successfully).

metrics: log whether drives have seek penalties (and whether this was determined successfully).

R=asvitkine@chromium.org
BUG=463209
Committed: https://crrev.com/9c09b08ce98ae3e25b2c3b248aa642eb2bff178c
Cr-Commit-Position: refs/heads/master@{#321257}

[Dan Beam, 2015-03-17 23:56:37]

dbeam@chromium.org changed reviewers:
+ asvitkine@chromium.org

[Dan Beam, 2015-03-18 00:00:59]

Patchset #1 (id:1) has been deleted

[Dan Beam, 2015-03-18 00:01:35]

asvitkine@: is this what you had in mind?

[Dan Beam, 2015-03-18 17:25:00]

Patchset #1 (id:20001) has been deleted

[Dan Beam, 2015-03-18 18:10:13]

Patchset #2 (id:60001) has been deleted

[Dan Beam, 2015-03-18 18:10:18]

Patchset #1 (id:40001) has been deleted

[Dan Beam, 2015-03-18 18:11:33]

dbeam@chromium.org changed reviewers:
+ mpearson@chromium.org
- asvitkine@chromium.org

[Dan Beam, 2015-03-18 18:11:33]

-asvitkine@ (ooo), +mpearson@

mpearson@: though the code lives in a metrics provider, it's just UMA_* stuff

[Mark P, 2015-03-18 18:17:43]

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:10988: +    Whether a drive has a seek
penalty (i.e. is a spinning disk).
All histograms should mention when they're recorded.  e.g., Emitted shortly
after startup when constructing the initial UMA log.
(I think that's right; correct me if I'm wrong.)

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:10996: +    This can fail when drivers
don't offer this information.
drivers?
drives?

[Dan Beam, 2015-03-18 18:33:20]

Patchset #3 (id:120001) has been deleted

[Dan Beam, 2015-03-18 18:33:25]

Patchset #2 (id:100001) has been deleted

[Dan Beam, 2015-03-18 18:33:52]

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:10988: +    Whether a drive has a seek
penalty (i.e. is a spinning disk).
On 2015/03/18 18:17:43, Mark P wrote:
> All histograms should mention when they're recorded.  e.g., Emitted shortly
> after startup when constructing the initial UMA log.
> (I think that's right; correct me if I'm wrong.)

Done.

https://codereview.chromium.org/1011093004/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:10996: +    This can fail when drivers
don't offer this information.
On 2015/03/18 18:17:43, Mark P wrote:
> drivers?
> drives?

actually meant drivers but technically both are correct (the driver tells the
system the capabilities of the drive).

see updated comment

[Mark P, 2015-03-18 18:45:46]

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
tools/metrics/histograms/histograms.xml:10989: +    shortly after startup when
constructing the initial UMA log.
Please put this last sentence in the other histograms as well.

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
tools/metrics/histograms/histograms.xml:11007: +    (currently twice shortly
after startup).
Is this last point (recorded twice) true for the other histograms as well?  If
so, say so on those places.  Not everyone will read all these three descriptions
at the same time.  They all read all the relevant information in each of them.

[Dan Beam, 2015-03-18 19:19:42]

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
tools/metrics/histograms/histograms.xml:10989: +    shortly after startup when
constructing the initial UMA log.
On 2015/03/18 18:45:46, Mark P wrote:
> Please put this last sentence in the other histograms as well.

Done.

https://codereview.chromium.org/1011093004/diff/140001/tools/metrics/histogra...
tools/metrics/histograms/histograms.xml:11007: +    (currently twice shortly
after startup).
On 2015/03/18 18:45:46, Mark P wrote:
> Is this last point (recorded twice) true for the other histograms as well?  If
> so, say so on those places.  Not everyone will read all these three
descriptions
> at the same time.  They all read all the relevant information in each of them.

Done.

[Mark P, 2015-03-18 19:32:52]

lgtm

[Dan Beam, 2015-03-18 22:42:43]

The CQ bit was checked by dbeam@chromium.org

[commit-bot: I haz the power, 2015-03-18 22:43:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1011093004/160001

[commit-bot: I haz the power, 2015-03-19 00:52:39]

Committed patchset #3 (id:160001)

[commit-bot: I haz the power, 2015-03-19 00:53:40]

Patchset 3 (id:??) landed as
https://crrev.com/9c09b08ce98ae3e25b2c3b248aa642eb2bff178c
Cr-Commit-Position: refs/heads/master@{#321257}

[Alexei Svitkine (slow), 2015-03-30 20:06:44]

asvitkine@chromium.org changed reviewers:
+ asvitkine@chromium.org

[Alexei Svitkine (slow), 2015-03-30 20:06:45]

lgtm