How to Deal with Android Size Alerts
Not all alerts should not have a bug created for them. Please read on...
Step 1: Identify the Commit
MonochromePublic.apk Alerts (Single Commit)
- Zoom in on the graph to make sure the alert is not off-by-one
&rev=COMMIT_POSITION in the URL.
- It will be obvious from this whether or not the point is off. Use the “nudge” feature to correct it when this happens.
MonochromePublic.apk Alerts (Multiple Commits or Rolls)
- Bisects will not help you.
- For rolls, you can sometimes guess the commit(s) that caused the regression by looking at the
android-binary-size trybot result for the roll commit.
- Otherwise, use diagnose_bloat.py in a local Android checkout to build all commits locally and find the culprit.
- Go to step 2.
tools/binary_size/diagnose_bloat.py AFTER_GIT_REV --reference-rev BEFORE_GIT_REV --subrepo v8 --all
- You can usually find the before and after revs in the roll commit message (example)
- Note that you may need to click through the link for the list of changes in order to find the actual first commit hash and use that one instead since some rollers (including v8) use extra commits for tagging not in master. In the linked example
BEFORE_GIT_REV would actually be
876f37c and not
Monochrome.apk (downstream) Alerts
- The regression most likely already occurred in the upstream MonochromePublic.apk target. Look at the graph of Monochrome.apk and MonochromePublic.apk overlaid to find the culprit and de-dupe with upstream alert.
- If no upstream regression was found, look through the downstream commits within the given date range to find the culprit.
git log --format=fuller (be sure to look at
CommitDate and not
- If the culprit is not obvious, follow the steps from the “multiple commits” section above, filing a bug and running
Step 2: File Bug or Silence Alert
- If the commit message's
Binary-Size: footer clearly justifies the size increase, silence the alert.
- If the regression is < 100kb and caused by an AFDO roll, silence the alert.
Otherwise, file a bug (TODO: Make this template automatic):
- Change the bug's title from
- Assign to commit author
- Set description to (replacing bold parts):
Caused by “First line of commit message”
Link to size graph: https://chromeperf.appspot.com/report?sid=bb23072657e2d7ca892a1c3fa4643b1ee29b3a0a44d0732adda87168e89c0380&num_points=10&rev=$CRREV
Link to trybot result: https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-binary-size/$TRYJOB_NUMBER
Debugging size regressions is documented at: https://chromium.googlesource.com/chromium/src/+/master/docs/speed/apk_size_regressions.md#Debugging-Apk-Size-Increase
Based on the trybot result: 20kb of native code, 8kb of pngs. (or some other explanation as to what caused the growth).
It's not clear to me whether or not this increase was expected.
Please have a look and either:
- Close as “Won't Fix” with a short justification, or
- Land a revert / fix-up.
It typically takes about a week of engineering time to reduce binary size by 50kb so we'd really appreciate you taking some time exploring options to address this regression!
If the regression is >50kb, add ReleaseBlock-Stable M-## (next branch cut).*
Debugging Apk Size Increase
Step 1: Identify what Grew
Figure out which file within the
.apk increased (native library, dex, pak resources, etc.) by looking at the trybot results or size graphs that were linked from the bug (if it was not linked in the bug, see above).
See //docs/speed/binary_size/metrics.md for a description of high-level binary size metrics.
See //tools/binary_size/README.md for a description of binary size tools.
Step 2: Analyze
Growth is from Translations
- There is likely nothing that can be done. Translations are expensive.
- Close as
Growth is from Native Resources (pak files)
compress="gzip" is used for all
- Look at the SuperSize reports from the trybot to look for unexpected resources, or unreasonably large symbols.
Growth is from Images
Growth is from Native Code
- Look at the SuperSize reports from the trybot to look for unexpected symbols, or unreasonably large symbols.
- If the diff looks reasonable, close as
- Otherwise, try to refactor a bit (e.g. move code out of templates).
- If symbols are larger than expected, use the
Disassemble() feature of
supersize console to see what is going on.
Growth is from Java Code
- Look at the SuperSize reports from the trybot to look for unexpected methods.
- Ensure any new Java deps are as specific as possible.
- If the change doesn't look suspect, check to see if the regression still exists when internal proguard is used (see downstream graphs or use
diagnose_bloat.py -v --enable-chrome-android-internal REV to build locally)
Growth is from “other lib size” or “Unknown files size”
You Would Like Assistance
For Binary Size Sheriffs
Step 1: Check Work Queue Daily
- Bugs requiring sheriffs to take a look at are labeled
- After resolving the bug by finding an owner or debugging or commenting, remove the
Step 2: Check Alerts Regularly
- IMPORTANT: Check the perf bot page several times a day to make sure it isn't broken (and ping/file a bug if it is).
- At the very least you need to check this once in the morning and once in the afternoon.
- If you don't and the builder is broken either you or the next sheriff will have to manually build and diff the broken range (via.
diagnose_bloat.py) to see if we missed any regressions.
- This is necessary even if the next passing build doesn't create an alert because the range could contain a large regression with multiple offsetting decreases.
- Check alert page regularly for new alerts.
- Join g/chrome-binary-size-alerts.
- Deal with alerts as outlined above.