Performance Improvement for SliverFillRemaining - #44471

Thank you @Piinks for improving the performance! It would be nice if you can add some performance test to capture and quantify your improvement. It will also prevent accidental performance regression in the future. See https://docs.google.com/document/d/1UolaKhEWieP2DDOhFuVQOuR5e545mO2obXcHH6p40Y4/edit#bookmark=id.70t9gnas5d1j for more info.

Please let me know if you have any questions about performance testing. I'm happy to answer them, or review the code in general.

I don't know that I have any baseline to measure a performance improvement for this change. This change is not motivated by a reported issue or performance problem. I am not sure how to capture or quantify any improvement then. 🙂

@Piinks : I see. The easiest way to get a baseline or to quantify the performance change is probably just running our existing tests. Have you noticed any difference in home_scroll_perf__timeline_summary, tiles_scroll_perf__timeline_summary, or home_scroll_perf__timeline_summary test before and after your patch?

(To run the test, cd flutter/flutter/dev/devicelab && ../../bin/cache/dart-sdk/bin/dart bin/run.dart -t <test_name>)

Ah! Thanks! I will check that out and report back! 💯

Looks like a minor improvement for home_scroll_perf__timeline_summary 90th_percentile_frame_rasterizer_time_millis. 🙂 Cool!

Good to hear @Piinks ! In that case you probably don't need to write a new performance test. Can you please post your local test result to this PR's description for future reference?

Perf test results after latest merge from master. :)

"success": true,
  "data": {
    "average_frame_build_time_millis": 2.928195402298851,
    "90th_percentile_frame_build_time_millis": 6.189,
    "99th_percentile_frame_build_time_millis": 9.166,
    "worst_frame_build_time_millis": 43.872,
    "missed_frame_build_budget_count": 1,
    "average_frame_rasterizer_time_millis": 7.273534482758619,
    "90th_percentile_frame_rasterizer_time_millis": 15.027,
    "99th_percentile_frame_rasterizer_time_millis": 21.857,
    "worst_frame_rasterizer_time_millis": 51.239,
    "missed_frame_rasterizer_budget_count": 14,
    "frame_count": 174,

@Piinks : are you waiting for some framework expert to review this PR? (Just found this lonely PR again in the performance triage.)

Hey @liyuqian, thank you. Yes this is waiting on a review. Would you like to give it a look? It is a fairly trivial change.