Related: we do actually measure the SI count for android:
https://chromeperf.appspot.com/report?sid=2e1421013ce75306cdc0974cbd058b84083ef684dabed256879bacb31613b326&num_points=5000

The missing step here is making it fail when the number increases. I'm not sure how this is implemented for sizes (is there a whitelist of existing SIs somewhere?).

Tommy - do you happen to have a link to a bot that shows a failing sizes step?

Also - looks like Android has ~60 SIs, whereas linux has only ~10:
https://chromeperf.appspot.com/report?sid=c64ba93e0a8bf806b6e6ce6ab646e3c963f03ea8dcff4a70efaf8bd9e3ab62ad&num_points=5000

Of course! :-)

https://luci-milo.appspot.com/buildbot/chromium/Linux%20x64/41189
https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Fchromium%2FLinux_x64%2F41189%2F%2B%2Frecipes%2Fsteps%2Fsizes%2F0%2Fstdout

Thanks. Lead me right to:
https://cs.chromium.org/chromium/src/testing/scripts/sizes.py?type=cs

Looks like we just have a .json file with the number of expected SIs:
https://cs.chromium.org/chromium/src/tools/perf_expectations/perf_expectations.json

From its history, it looks like it used to also have limits for ELF section sizes, but they were removed due since people just updated them whenever limits were hit.

Having the script fail when SIs increase wouldn't actually be the useful at the moment, since resource_sizes.py is not run by any trybots. For now, it's probably just as easy to add a perf alert for SIs increasing. I've noted that we should add this to the bug on adding a resource_sizes trybot:  bug 702625 

Filed monitoring bug 730274.

Note: Another alternative would be to add checking of SIs to linux_android_rel_ng. I hope to be able to work on  bug 702625  next quarter though, so easier to just wait on that for now.

Monitoring set up, and better trybot-time failures tracked by  bug 702625 . Closing.

FYI - The move to clang got rid of a lot of SIs!
https://bugs.chromium.org/p/chromium/issues/detail?id=729847

https://chromeperf.appspot.com/report?sid=e0a3413f2dc96f8600f045642abbbab6691b110b976ba2136bf38eaed02c8aa0&start_rev=477987&end_rev=479207