Replace multiprocessing with threading in memory_inspector

Replace multiprocessing with threading in memory_inspector

This patch is part of an ongoing process to unbundle memory_inspector
and make it a chrome app. It replaces multiprocessing, which is
currently not supported by naclports/python, with threading.

BUG=448399
Committed: https://crrev.com/74e86ded0d45b7e80158dbbdf6b54063ac851042
Cr-Commit-Position: refs/heads/master@{#311515}

[petrcermak, 2015-01-14 10:53:48]

petrcermak@chromium.org changed reviewers:
+ primiano@chromium.org

[Primiano Tucci (use gerrit), 2015-01-14 12:17:23]

Thanks, just few comments

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
File tools/memory_inspector/memory_inspector/frontends/background_tasks.py
(right):

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:20: import
threading
nit: alpha sorting

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:54: for
proc in _tasks.itervalues():
Since this is not a process anymore can you just rename this to "task"?
Thanks

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:148:
*sys.exc_info()[:2])[-1].strip()))
2 things here:
1) I think you can get the exception with traceback.format_exc() without having
to use sys.exc_info()

2) Can you just spend an extra line to make clear what you get after the the
string manipulation math [:2][-1].split()

something like:
boh = traceback.format_exc()[...]
self._log_queue.put(100, boh)

[Primiano Tucci (use gerrit), 2015-01-14 12:17:25]

Thanks, just few comments

[petrcermak, 2015-01-14 13:43:32]

Thanks for your comments. PTAL.

Petr

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
File tools/memory_inspector/memory_inspector/frontends/background_tasks.py
(right):

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:20: import
threading
On 2015/01/14 12:17:23, Primiano Tucci wrote:
> nit: alpha sorting

Done.

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:54: for
proc in _tasks.itervalues():
On 2015/01/14 12:17:23, Primiano Tucci wrote:
> Since this is not a process anymore can you just rename this to "task"?
> Thanks

Done.

https://codereview.chromium.org/836933004/diff/1/tools/memory_inspector/memor...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:148:
*sys.exc_info()[:2])[-1].strip()))
On 2015/01/14 12:17:23, Primiano Tucci wrote:
> 2 things here:
> 1) I think you can get the exception with traceback.format_exc() without
having
> to use sys.exc_info()

traceback.format_exc() includes the traceback, which I presume we don't want to
show in the memory_inspector trace (It will still show in the log anyway).

> 2) Can you just spend an extra line to make clear what you get after the the
> string manipulation math [:2][-1].split()
> 
> something like:
> boh = traceback.format_exc()[...]
> self._log_queue.put(100, boh)

Done.

[petrcermak, 2015-01-14 15:14:23]

I simplified the error logging as discussed offline.

Petr

[Primiano Tucci (use gerrit), 2015-01-14 17:17:00]

LGTM % 2 nits, thanks

https://codereview.chromium.org/836933004/diff/40001/tools/memory_inspector/m...
File tools/memory_inspector/memory_inspector/frontends/background_tasks.py
(right):

https://codereview.chromium.org/836933004/diff/40001/tools/memory_inspector/m...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:21: import
sys
Nit: You don't need thi (And traceback) anymore

[Primiano Tucci (use gerrit), 2015-01-14 17:17:02]

LGTM % 2 nits, thanks

[petrcermak, 2015-01-14 17:25:26]

https://codereview.chromium.org/836933004/diff/40001/tools/memory_inspector/m...
File tools/memory_inspector/memory_inspector/frontends/background_tasks.py
(right):

https://codereview.chromium.org/836933004/diff/40001/tools/memory_inspector/m...
tools/memory_inspector/memory_inspector/frontends/background_tasks.py:21: import
sys
On 2015/01/14 17:17:00, Primiano Tucci wrote:
> Nit: You don't need thi (And traceback) anymore

Done. Thanks for spotting this.

[petrcermak, 2015-01-14 17:25:29]

The CQ bit was checked by petrcermak@chromium.org

[commit-bot: I haz the power, 2015-01-14 17:26:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/836933004/60001

[commit-bot: I haz the power, 2015-01-14 18:20:21]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-01-14 18:21:20]

Patchset 4 (id:??) landed as
https://crrev.com/74e86ded0d45b7e80158dbbdf6b54063ac851042
Cr-Commit-Position: refs/heads/master@{#311515}