Any thoughts on this? I'm experimenting with #5. It's pretty handy. The only problems are:
1) StartTracing takes quite a while - can this be improved?
2) StopTracing exits battor_agent.exe. Is it practical to have it stay running?

I forgot to tag this bug on the first change in this series, so I'm copying the data over:

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/df2314bc8403a7ecab565bf990cf4ec54fc21127

commit df2314bc8403a7ecab565bf990cf4ec54fc21127
Author: Bruce Dawson <brucedawson@chromium.org>
Date: Thu Aug 03 17:39:31 2017

Improve OOB experience for battor_agent

When running battor_agent.exe for the first time one is likely to
encounter the message "Unable to find a BattOr." Once a BattOr is found
and battor_agent starts running there is a more informative help message
printed if you type <enter>, but that is too late. This change prints an
informative help message when a BattOr cannot be found, and also adds a
bug link to the code to explain why BattOrs are not auto-found on
Windows.

BUG=  588244  

Change-Id: I1206f906b32c2f2e6ec18517e6c184aaf44bb7a7
Reviewed-on: https://chromium-review.googlesource.com/598657
Reviewed-by: Charlie Andrews <charliea@chromium.org>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491779}
[modify] https://crrev.com/df2314bc8403a7ecab565bf990cf4ec54fc21127/tools/battor_agent/battor_agent_bin.cc
[modify] https://crrev.com/df2314bc8403a7ecab565bf990cf4ec54fc21127/tools/battor_agent/battor_finder.cc

Bruce.

I like these ideas. We didn't really have any human CLI users of battor_agent until now, that's why the functionality is missing. As long as you preserve the functionality that we need in the perf infra (e.g., writing samples to files), I think these usability things would be great.

Would the ETW trace events allow us to automatically sync ETW and BattOr in the trace-viewer data that is collected on the BattOr infra?

The ETW trace events would let us easily manually line up BattOr data viewed in Chrome with ETW data viewed in WPA. However, this alignment would become unmanageable as we zoom into the data, so it has limited utility.

https://codereview.appspot.com/326950043 is a partial proof of concept of how the integration could possibly be done properly.

Would it be reasonable to have the default before for StopTracing with no parameters to be to print the average power draw in Watts, or should that be optional?

Bruce: there is this doc written long time ago about how we do clock syncing: https://bit.ly/tracing-clock-sync 

Maybe this could be interesting you, so I thought I gonna share :-)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e3324e02024d47b835ef998d49d1d8f82debe4fb

commit e3324e02024d47b835ef998d49d1d8f82debe4fb
Author: Bruce Dawson <brucedawson@chromium.org>
Date: Fri Sep 01 18:17:00 2017

Add interactive mode to battor_agent

battor_agent is clumsy to use interactively because you have to type
full commands. This adds an interactive mode (enabled with --interactive
on the command line) where typing Enter toggles between StartTracing and
StopTracing. Printing a tidy summary of the results will be added in a
separate CL.

BUG= 751863 

Change-Id: I026821b438499d4826c9ccc07f3e3e0255d5da6a
Reviewed-on: https://chromium-review.googlesource.com/638351
Reviewed-by: Charlie Andrews <charliea@chromium.org>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#499232}
[modify] https://crrev.com/e3324e02024d47b835ef998d49d1d8f82debe4fb/tools/battor_agent/battor_agent_bin.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6cca2c085e74f850f05746a13649d05a1b026ac5

commit 6cca2c085e74f850f05746a13649d05a1b026ac5
Author: Bruce Dawson <brucedawson@chromium.org>
Date: Thu Sep 07 18:47:24 2017

Improve battor_agent interactive mode

The battor_agent StopTracing command, if no file name is specified,
printed the raw sampling data which can easily be 100,000 lines of
numbers. This is not helpful. This change improves this case,
especially when in interactive mode.

Now a BattorResults object is returned which contains a detailed
string representation of the results and enough information to allow
creating a summary. When in battor_agent's interactive mode the
summary is printed and the details are saved to a file (using a
generated file name if none is supplied). The summary result format
is for human consumption and is subject to change but currently it
looks like this:

StopTracing
Second  0 average power:  9.20 W
Second  1 average power:  8.65 W
Second  2 average power: 11.38 W
Average power over 3.14 s :  9.74 W
Summary of power-by-seconds:
Minimum:  8.65
Median:   9.20
Maximum: 11.38
Saving detailed results to c:\users\brucedawson\desktop\trace_data.txt
Done.

This lets the developer easily see the average power and the variability
of power, which is helpful for getting a sense of how consistent the
results are and therefore (in steady-state scenarios) how meaningful
they are. This format has been tested for a few weeks on a Battor
equipped SurfaceBook.

Bug:  751863 
Change-Id: I57af162f183a4d65388c88c901573cd6720ae2b8
Reviewed-on: https://chromium-review.googlesource.com/609385
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Reviewed-by: Charlie Andrews <charliea@chromium.org>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#500344}
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/content/browser/tracing/power_tracing_agent.cc
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/content/browser/tracing/power_tracing_agent.h
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_agent.cc
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_agent.h
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_agent_bin.cc
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_agent_unittest.cc
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_sample_converter.cc
[modify] https://crrev.com/6cca2c085e74f850f05746a13649d05a1b026ac5/tools/battor_agent/battor_sample_converter.h

Battor is being deprecated so no more work on this is needed. Some data was obtained from Battor, but I found that the local-testing results were too noisy to be very useful.