Add three new histogram to tracking QUIC packet reordering:

Add two new histogram to tracking QUIC packet reordering:
* Net.QuicSession.MaxReordering
* Net.QuicSession.MaxReorderingTime
* Net.QuicSession.MaxReorderingTimeLongRtt

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272631

[Ryan Hamilton, 2014-05-23 15:34:39]

Ian, I think this is what we discussed. What do you think?

[Ian Swett, 2014-05-23 15:54:35]

lgtm

Thanks Ryan, it would be nice to have a matching reordering in sequence number
space as well, so we have a clean comparison of what thresholds we'd need to
deal with X% reordering for either approach.

https://codereview.chromium.org/298893010/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/298893010/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:13549: +<histogram
name="Net.QuicSession.MaxReorderingTime" units="percent">
I think it'd be worth being clear that this is percent, not an absolute time.

[Ian Swett, 2014-05-23 15:56:23]

lgtm

One more nit about the new histogram, but LGTM.

https://codereview.chromium.org/298893010/diff/20001/tools/metrics/histograms...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/298893010/diff/20001/tools/metrics/histograms...
tools/metrics/histograms/histograms.xml:13551: +  <summary>The maximum
reordering observed by a QUIC connection.</summary>
Nit: comment that it's in sequence number space?

[commit-bot: I haz the power, 2014-05-23 15:57:59]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rch@chromium.org/298893010/40001

[commit-bot: I haz the power, 2014-05-23 15:58:00]

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

[commit-bot: I haz the power, 2014-05-23 15:58:00]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Ryan Hamilton, 2014-05-23 16:19:15]

jar: can you take a look?

https://codereview.chromium.org/298893010/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/298893010/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:13549: +<histogram
name="Net.QuicSession.MaxReorderingTime" units="percent">
On 2014/05/23 15:54:35, Ian Swett wrote:
> I think it'd be worth being clear that this is percent, not an absolute time.

Right, that's why it has units="percent"

https://codereview.chromium.org/298893010/diff/20001/tools/metrics/histograms...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/298893010/diff/20001/tools/metrics/histograms...
tools/metrics/histograms/histograms.xml:13551: +  <summary>The maximum
reordering observed by a QUIC connection.</summary>
On 2014/05/23 15:56:23, Ian Swett wrote:
> Nit: comment that it's in sequence number space?

Done.

[jar (doing other things), 2014-05-23 16:24:49]

lgtm

https://codereview.chromium.org/298893010/diff/60001/tools/metrics/histograms...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/298893010/diff/60001/tools/metrics/histograms...
tools/metrics/histograms/histograms.xml:13566: +    The ratio of the maximum
reordering time of a QUIC packet to the min rtt,
nit: to reduce replication of prose, we often use the "field_trial" construct in
this file to suggest "alternate continuations of the histogram name" as well as
the associated "additional prose."  You named the histograms perfectly for using
this pattern.

In this case, with such a small amount of prose... and only one replication, it
is borderline... but it is often the case that the list grows, and having the
field trial just simplifies things.

In this case, it is fifty-fifty about which is better... and this is done... so
I'll LGTM.

[commit-bot: I haz the power, 2014-05-23 20:25:52]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-05-23 23:17:11]

Change committed as 272631