Closed
Bug 1641073
Opened 5 years ago
Closed 5 years ago
mozpack: copying files uses inefficient string concatenation
Categories
(Firefox Build System :: General, enhancement)
Firefox Build System
General
Tracking
(firefox78 fixed)
RESOLVED
FIXED
mozilla78
| Tracking | Status | |
|---|---|---|
| firefox78 | --- | fixed |
People
(Reporter: mhentges, Assigned: mhentges)
Details
Attachments
(1 file)
When toolkit/mozilla/installer/unpack.py is invoked with python3 instead of python2, it takes ~60s instead of < 1s. This turns out to be because mozpack's BaseFile.copy() method is slow for large files.
The culprit of this performance issue is that string concatenation is slow since strings are immutable, and we are appending very large strings for large files.
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Assignee | |
Comment 1•5 years ago
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Arrays are mutable, so appending each substring at a time and joining at the endis much faster than re-allocating
a new string on each loop.
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Updated•5 years ago
|
Assignee: nobody → mhentges
Status: NEW → ASSIGNED
Pushed by mhentges@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/8a881029b6f9
improve BaseFile.copy() performance r=rstewart
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Comment 3•5 years ago
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| bugherder | ||
Status: ASSIGNED → RESOLVED
Closed: 5 years ago
status-firefox78:
--- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla78
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Description
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