[Findit] Use a thread pool.

[Findit] Use a thread pool.

Currently, Findit starts and joins threads in a few places. This is not elegant from the perspective of design and not good for performance due to the overhead of starting/joining of threads.

This CL is to create a shared thread pool to execute tasks just like a task queue.
 
NOTRY=true

Committed: https://crrev.com/41ddc64aba525d5ba456d7a45b2842bad8515c7f
Cr-Commit-Position: refs/heads/master@{#292985}

[stgao, 2014-08-29 22:47:36]

stgao@chromium.org changed reviewers:
+ aarya@google.com, mbarbella@chromium.org

[stgao, 2014-08-29 22:47:36]

https://codereview.chromium.org/525433003/diff/20001/tools/findit/common/http...
File tools/findit/common/http_client_local.py (right):

https://codereview.chromium.org/525433003/diff/20001/tools/findit/common/http...
tools/findit/common/http_client_local.py:231: print 'requesting url: %s' % url
I will revert this before committing.
I'm running the benchmark to check how many duplicate url request are there.

[stgao, 2014-08-29 22:48:49]

https://codereview.chromium.org/525433003/diff/20001/tools/findit/crash_utils.py
File tools/findit/crash_utils.py (right):

https://codereview.chromium.org/525433003/diff/20001/tools/findit/crash_utils...
tools/findit/crash_utils.py:19: MAX_THREAD_NUMBER = 10
How many threads do you guys prefer?

[aarya, 2014-08-31 01:02:29]

lgtm. 10 is fine. please update cf code as well.

[stgao, 2014-09-02 18:31:47]

The CQ bit was checked by stgao@chromium.org

[commit-bot: I haz the power, 2014-09-02 18:33:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/stgao@chromium.org/525433003/40001

[stgao, 2014-09-02 19:40:50]

The CQ bit was unchecked by stgao@chromium.org

[stgao, 2014-09-02 19:41:00]

The CQ bit was checked by stgao@chromium.org

[commit-bot: I haz the power, 2014-09-02 19:46:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/stgao@chromium.org/525433003/40001

[commit-bot: I haz the power, 2014-09-02 20:14:24]

Committed patchset #3 (id:40001) as e626b6cdd5117976c58cb4c4c9e12bad7c977658

[commit-bot: I haz the power, 2014-09-10 03:20:22]

Patchset 3 (id:??) landed as
https://crrev.com/41ddc64aba525d5ba456d7a45b2842bad8515c7f
Cr-Commit-Position: refs/heads/master@{#292985}

[stgao, 2016-05-12 23:37:29]

Description was changed from

==========
[Findit] Use a thread pool.

BUG=
NOTRY=true

Committed: https://crrev.com/41ddc64aba525d5ba456d7a45b2842bad8515c7f
Cr-Commit-Position: refs/heads/master@{#292985}
==========

to

==========
[Findit] Use a thread pool.

Currently, Findit starts and joins threads in a few places. This is not elegant
from the perspective of design and not good for performance due to the overhead
of starting/joining of threads.

This CL is to create a shared thread pool to execute tasks just like a task
queue.
 
NOTRY=true

Committed: https://crrev.com/41ddc64aba525d5ba456d7a45b2842bad8515c7f
Cr-Commit-Position: refs/heads/master@{#292985}
==========