[Telemetry] Cause web server to keep resources in memory and thread requests.

[Telemetry] Cause web server to keep resources in memory and thread requests.

My hope is that this will solve the noise problem on the perf bots. The theory
being that the disk accesses in a single-threaded HTTP server could cause
significant hiccups in the page loads.

To accomplish this, we extend SimpleHTTPServer and override the key methods to
serve from an in-memory cache rather than by reading from disk for each URL.

Unfortunately, the page_cycler data directory is >300M, so to avoid reading in
the whole thing, the page_cycler page_sets now specify the directories that they
actually need.

BUG=196411
TEST=Ran various benchmarks and unittests
NOTRY=True

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=189958

[tonyg, 2013-03-22 23:41:15]

ptal, this CL isn't actually as big as it looks. I just had to update all the
page_cycler page_sets.

[nduca, 2013-03-23 00:09:06]

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
File tools/telemetry/telemetry/core/browser.py (right):

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/browser.py:175: def SetHTTPServerDirectory(self,
paths):
should we tweak this name to be more plural? SetHTTPServingDirectories or
whatever?

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/browser.py:176: if paths and self._http_server
and self._http_server.paths == paths:

is array equality what we want here?

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
File tools/telemetry/telemetry/core/memory_cache_http_server.py (right):

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/memory_cache_http_server.py:76: def
test(HandlerClass=MemoryCacheHTTPRequestHandler,
def Main(args):
  <insert the SimpleHTTPServer.test function here>

[nduca, 2013-03-23 00:09:17]

(lgtm)

[tonyg, 2013-03-23 00:27:21]

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
File tools/telemetry/telemetry/core/browser.py (right):

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/browser.py:175: def SetHTTPServerDirectory(self,
paths):
On 2013/03/23 00:09:06, nduca wrote:
> should we tweak this name to be more plural? SetHTTPServingDirectories or
> whatever?

Done.

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/browser.py:176: if paths and self._http_server
and self._http_server.paths == paths:
On 2013/03/23 00:09:06, nduca wrote:
> 
> is array equality what we want here?

This is python :)

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
File tools/telemetry/telemetry/core/memory_cache_http_server.py (right):

https://codereview.chromium.org/12813013/diff/1/tools/telemetry/telemetry/cor...
tools/telemetry/telemetry/core/memory_cache_http_server.py:76: def
test(HandlerClass=MemoryCacheHTTPRequestHandler,
On 2013/03/23 00:09:06, nduca wrote:
> def Main(args):
>   <insert the SimpleHTTPServer.test function here>

Done.

[tonyg, 2013-03-23 00:29:57]

Committed patchset #2 manually as r189958 (presubmit successful).