1039571 - Decrease the number of times we parse the manifest inside runtests.py

Status: RESOLVED WONTFIX

(Testing :: Mochitest, defect)

Description

[Vaibhav (:vaibhav1994)]

We parse the manifest 3 times inside runtests.py, when we call the getActiveTests function:

1) http://dxr.mozilla.org/mozilla-central/source/testing/mochitest/runtests.py#1384

2) http://dxr.mozilla.org/mozilla-central/source/testing/mochitest/runtests.py#466

3) inside the getDirectories function: http://dxr.mozilla.org/mozilla-central/source/testing/mochitest/runtests.py#1865

If we can decrease the number of times manifests are parsed, it will make the code better and reduce the runtime.

Comment 1

[Vaibhav (:vaibhav1994)]

I think that removing of parsing manifest in getDirectories is not a good idea because we still have to filter the tests to run for each loop which will still have almost the same time complexity as the current implementation.

Comment 2

[Joel Maher ( :jmaher ) (UTC -8)]

that makes sense. I am not worried about overhead of parsing, just not doing something twice if we don't need to.

Can we parse the list once and keep it as a master list, then pass the current list to our loop?  If that doesn't make sense, then we can resolve this as wontfix.

Comment 3

[Vaibhav (:vaibhav1994)]

Yes, we may keep a master list but that will add a lot of overhead if we add more functions in future, plus we are not saving significant time.

Also, we need to have a call to getActiveTests method in buildTestPath because b2g emulator directly calls the function to parse manifest. I did a try run by removing the parsing of manifest: https://tbpl.mozilla.org/?tree=Try&rev=a56913e0af1, but it failed on b2g emulator.