telemetry: Fix runaway subprocess in monsoon_power_monitor.py

telemetry: Fix runaway subprocess in monsoon_power_monitor.py

Telemetry leaves a memory hogging subprocess behind if:
1) A Monsoon Power Monitor is attached to host computer (Linux),
2) User runs a power-metric-using benchmark such as sunspider on Android
   ChromeShell, and
3) Benchmark raises an exception between power metric's Start and Stop
   calls. For example, an exception will occur if browser crashes and
   the benchmark does something like tab.WaitForJavaScriptExpression().

This patch fixes the issue by setting the daemon flag on the subprocess.
This will cause the main process to kill the subprocess on exit.

BUG=413596
R=ernstm@chromium.org

Committed: https://crrev.com/362315d0dee01153479d649db12e1e6edd2622af
Cr-Commit-Position: refs/heads/master@{#296177}

[v.putkinen, 2014-09-15 13:09:37]

v.putkinen@partner.samsung.com changed reviewers:
+ qsr@chromium.org, tmandel@chromium.org, tonyg@chromium.org

[v.putkinen, 2014-09-15 13:13:10]

v.putkinen@partner.samsung.com changed reviewers:
+ chrishenry@google.com, dtu@chromium.org, marja@chromium.org

[v.putkinen, 2014-09-15 13:15:37]

I'd like you to review my Telemetry patch.

[dtu, 2014-09-15 21:33:25]

On 2014/09/15 13:15:37, v.putkinen wrote:
> I'd like you to review my Telemetry patch.

If this is your first patch, you need to fill out a Contributor License
Agreement.

Here's the Corporate version (I assume you're contributing on the behalf of
Samsung):
https://developers.google.com/open-source/cla/corporate?csw=1

Barring that legal detail, this patch lgtm

[v.putkinen, 2014-09-16 21:48:11]

On 2014/09/15 21:33:25, dtu wrote:
> If this is your first patch, you need to fill out a Contributor License
> Agreement.

Thanks for the quick review!

I just submitted an Individidual CLA since that seems to be the Samsung policy
as far as I can tell.

[achuithb, 2014-09-17 13:37:57]

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

[achuithb, 2014-09-17 13:37:58]

https://codereview.chromium.org/572643002/diff/20001/tools/telemetry/telemetr...
File
tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
(right):

https://codereview.chromium.org/572643002/diff/20001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py:77:
self._powermonitor_process.daemon = 1
True? Isn't this a Boolean?

[v.putkinen, 2014-09-18 07:32:47]

On 2014/09/16 21:48:11, v.putkinen wrote:
> I just submitted an Individidual CLA since that seems to be the Samsung policy
> as far as I can tell.

Oops, actually Samsung does have a Corporate CLA. I was added there a moment
ago, so this CLA thing should be cleared now.

[v.putkinen, 2014-09-18 07:33:54]

https://codereview.chromium.org/572643002/diff/20001/tools/telemetry/telemetr...
File
tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
(right):

https://codereview.chromium.org/572643002/diff/20001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py:77:
self._powermonitor_process.daemon = 1
On 2014/09/17 13:37:58, achuithb wrote:
> True? Isn't this a Boolean?

It is, good catch. I'll send a fixed patch set with "= True" when I get back to
work from sick leave.

[achuithb, 2014-09-23 12:48:33]

The CQ bit was checked by achuith@chromium.org

[achuithb, 2014-09-23 12:48:33]

lgtm

Looks like this was fixed.

[commit-bot: I haz the power, 2014-09-23 12:49:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/572643002/40001

[commit-bot: I haz the power, 2014-09-23 14:29:33]

Committed patchset #3 (id:40001) as 2abfdfaa32c7f43aceef504963ccac65ee04f7b8

[commit-bot: I haz the power, 2014-09-23 14:30:23]

Patchset 3 (id:??) landed as
https://crrev.com/362315d0dee01153479d649db12e1e6edd2622af
Cr-Commit-Position: refs/heads/master@{#296177}