1134800 - mozpack.path.match doesn't properly cache patterns

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Gregory Szorc [:gps]]

We have a regular expression cache in mozpack.path.match. Unfortunately it isn't being used properly and the cache is never getting hit. This is resulting in some performance issues with the work in bug 1132111.

Comment 1

[Gregory Szorc [:gps]]

Attachment: Properly cache file matching patterns

The regular expression cache for mozpack.path.match was keyed off the
original pattern. However, that variable was mutated as part of the
function and the mutated result was subsequently stored as the cache
key. This effectively resulted in a 0% cache hit rate.

On some tests being written for bug 1132111 which involve a full
filesystem traversal for moz.build files and subsequent execution of
those files, the following timings are indicative of the impact of this
patch.

Before:
real 16.082s
user 14.760s
sys   1.318s

After:
real 6.345s
user 5.085s
sys  1.257s

Comment 2

[Gregory Szorc [:gps]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/671693d4fcf4

Comment 3

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/671693d4fcf4