[analyzer] Stable analysis tool has more options The CL adds options to disable comments, disable warnings and disable lints. It also makes the cfe "compile_files_in_folders" tool ignore these settings. Disabling comments, for instance, looks to give a change of: * instructions:u between -6.79% and -7.99%. * msec task-clock:u between -6.72% and -11.21%. * seconds time elapsed between -6.71 and -11.21%. depending on what other options are given (disabling lints and/or warnings too) and whether GC is "disabled" or not. See below for details. Similarly disabling lints (the 14 lints I've otherwise enabled) (although less combinations tested) seems to change the cost between -2.11% and -3.33%, and disabling warnings seems to change the cost between -7.60% and -13.28%. In total either enabling both lints, warnings and comments vs neither (disabling all three) change the cost -16.29% and -21.86%. Comparing a CFE compile with an analyzer "compile" with all three disabled shows that analyzer is still about twice as slow. Details: ``` $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot) with snapshot #2 (stable_analysis.aot --no-comments) msec task-clock:u: -7.0360% +/- 2.2215% (-716.15 +/- 226.12) (10178.40 -> 9462.25) page-faults:u: -9.3094% +/- 0.0553% (-16061.70 +/- 95.37) (172531.70 -> 156470.00) cycles:u: -6.9440% +/- 2.2933% (-2972501432.70 +/- 981663660.71) (42806647619.00 -> 39834146186.30) instructions:u: -6.7931% +/- 0.0048% (-3440120947.40 +/- 2430899.72) (50641327831.60 -> 47201206884.20) seconds time elapsed: -7.0392% +/- 2.2165% (-0.72 +/- 0.23) (10.18 -> 9.47) seconds user: -6.9201% +/- 2.3274% (-0.68 +/- 0.23) (9.83 -> 9.15) seconds sys: -10.2590% +/- 9.2097% (-0.04 +/- 0.03) (0.35 -> 0.31) Comparing GC runtimes: Combined GC time: -9.6583% +/- 1.7022% (-321.00 +/- 56.57) (3323.57 -> 3002.57) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot) with snapshot #2 (stable_analysis.aot --no-comments) msec task-clock:u: -7.1224% +/- 0.3630% (-1605.67 +/- 81.82) (22543.93 -> 20938.26) page-faults:u: -3.1600% +/- 0.0002% (-46716.10 +/- 2.42) (1478356.30 -> 1431640.20) cycles:u: -7.7156% +/- 0.3679% (-6694485059.90 +/- 319209763.53) (86765022635.00 -> 80070537575.10) instructions:u: -7.6201% +/- 0.0010% (-2695561907.00 +/- 362989.96) (35374252528.80 -> 32678690621.80) branch-misses:u: -10.2389% +/- 3.5180% (-11334840.10 +/- 3894561.73) (110703356.00 -> 99368515.90) seconds time elapsed: -7.1089% +/- 0.3612% (-1.60 +/- 0.08) (22.56 -> 20.95) seconds user: -7.4913% +/- 0.4934% (-1.51 +/- 0.10) (20.13 -> 18.62) seconds sys: -4.0502% +/- 3.7179% (-0.10 +/- 0.09) (2.42 -> 2.32) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-lints" --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot --no-lints) with snapshot #2 (stable_analysis.aot --no-comments --no-lints) msec task-clock:u: -9.2019% +/- 0.6621% (-910.34 +/- 65.50) (9892.93 -> 8982.59) page-faults:u: -6.2397% +/- 0.0494% (-10547.20 +/- 83.52) (169032.60 -> 158485.40) cycles:u: -9.3403% +/- 0.6697% (-3887793187.50 +/- 278762348.75) (41623774318.80 -> 37735981131.30) instructions:u: -7.0416% +/- 0.0016% (-3514960850.70 +/- 810910.06) (49917064106.10 -> 46402103255.40) branch-misses:u: -8.4057% +/- 2.6353% (-13819038.80 +/- 4332417.14) (164399864.10 -> 150580825.30) seconds time elapsed: -9.2035% +/- 0.6675% (-0.91 +/- 0.07) (9.90 -> 8.99) seconds user: -9.4766% +/- 0.7713% (-0.91 +/- 0.07) (9.55 -> 8.65) Comparing GC runtimes: Combined GC time: -11.4370% +/- 1.6980% (-378.03 +/- 56.13) (3305.37 -> 2927.33) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot --no-lints) with snapshot #2 (stable_analysis.aot --no-comments --no-lints) msec task-clock:u: -7.2817% +/- 0.4008% (-1593.44 +/- 87.70) (21882.89 -> 20289.45) page-faults:u: -3.1244% +/- 0.0002% (-45240.50 +/- 2.27) (1447974.10 -> 1402733.60) cycles:u: -7.9326% +/- 0.4361% (-6672136018.70 +/- 366778719.10) (84110098071.20 -> 77437962052.50) instructions:u: -7.4881% +/- 0.0026% (-2595260910.30 +/- 917003.73) (34658689885.60 -> 32063428975.30) branch-misses:u: -10.1639% +/- 3.2225% (-11069908.60 +/- 3509791.31) (108913984.10 -> 97844075.50) seconds time elapsed: -7.2712% +/- 0.4031% (-1.59 +/- 0.09) (21.90 -> 20.31) seconds user: -7.8503% +/- 0.5967% (-1.53 +/- 0.12) (19.53 -> 18.00) seconds sys: -2.5633% +/- 2.0326% (-0.06 +/- 0.05) (2.35 -> 2.29) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-lints" --sarguments="--no-warnings" --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --sarguments="--no-warnings" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot --no-lints --no-warnings) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -11.2175% +/- 0.9595% (-1057.47 +/- 90.45) (9427.00 -> 8369.53) page-faults:u: -2.9365% +/- 0.0303% (-4905.10 +/- 50.64) (167041.70 -> 162136.60) cycles:u: -11.5567% +/- 0.9943% (-4574393094.20 +/- 393550033.60) (39582014249.70 -> 35007621155.50) instructions:u: -7.9922% +/- 0.0016% (-3682331457.40 +/- 758149.87) (46074246049.70 -> 42391914592.30) branch-misses:u: -12.5973% +/- 3.8892% (-20502429.90 +/- 6329690.96) (162752151.40 -> 142249721.50) seconds time elapsed: -11.2137% +/- 0.9574% (-1.06 +/- 0.09) (9.43 -> 8.37) seconds user: -11.8730% +/- 1.0637% (-1.08 +/- 0.10) (9.10 -> 8.02) Comparing GC runtimes: Combined GC time: -11.6525% +/- 0.5882% (-393.43 +/- 19.86) (3376.40 -> 2982.97) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot --no-lints --no-warnings) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -6.7208% +/- 0.3612% (-1266.45 +/- 68.07) (18843.65 -> 17577.20) page-faults:u: -3.1649% +/- 0.0001% (-42088.20 +/- 1.96) (1329861.40 -> 1287773.20) cycles:u: -7.3160% +/- 0.4054% (-5241354807.90 +/- 290412282.62) (71642843105.80 -> 66401488297.90) instructions:u: -7.5935% +/- 0.0044% (-2296152115.10 +/- 1343905.59) (30238373990.20 -> 27942221875.10) branch-misses:u: -9.1132% +/- 3.9645% (-8608099.00 +/- 3744717.48) (94457321.20 -> 85849222.20) seconds time elapsed: -6.7108% +/- 0.3627% (-1.27 +/- 0.07) (18.86 -> 17.59) seconds user: -7.0670% +/- 0.5908% (-1.18 +/- 0.10) (16.67 -> 15.49) seconds sys: -4.0702% +/- 2.9649% (-0.09 +/- 0.06) (2.18 -> 2.09) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-warnings" --sarguments="--no-comments" --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --sarguments="--no-warnings" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot --no-warnings --no-comments) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -3.3341% +/- 0.7377% (-289.51 +/- 64.06) (8683.35 -> 8393.84) page-faults:u: -0.7417% +/- 0.0323% (-1211.60 +/- 52.80) (163349.30 -> 162137.70) cycles:u: -3.4347% +/- 0.7601% (-1248867985.60 +/- 276375749.53) (36360602643.40 -> 35111734657.80) instructions:u: -2.6297% +/- 0.0028% (-1144935784.80 +/- 1231115.23) (43538078747.80 -> 42393142963.00) branch-misses:u: -5.2678% +/- 3.3805% (-7994928.30 +/- 5130484.66) (151768514.80 -> 143773586.50) seconds time elapsed: -3.3345% +/- 0.7360% (-0.29 +/- 0.06) (8.69 -> 8.40) seconds user: -3.2817% +/- 0.7542% (-0.27 +/- 0.06) (8.35 -> 8.07) Comparing GC runtimes: No change in combined time. Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot --no-warnings --no-comments) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -2.9476% +/- 0.7598% (-533.40 +/- 137.48) (18095.98 -> 17562.59) page-faults:u: -2.1956% +/- 0.0002% (-28908.80 +/- 2.72) (1316679.70 -> 1287770.90) cycles:u: -3.0434% +/- 0.8290% (-2084711292.10 +/- 567884399.15) (68499834949.50 -> 66415123657.40) instructions:u: -2.1172% +/- 0.0036% (-604406330.20 +/- 1031078.80) (28547212878.80 -> 27942806548.60) seconds time elapsed: -2.9501% +/- 0.7589% (-0.53 +/- 0.14) (18.11 -> 17.58) seconds user: -2.7506% +/- 0.9446% (-0.44 +/- 0.15) (15.93 -> 15.49) seconds sys: -4.3950% +/- 4.3370% (-0.10 +/- 0.09) (2.17 -> 2.07) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-lints" --sarguments="--no-comments" --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --sarguments="--no-warnings" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot --no-lints --no-comments) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -7.6122% +/- 0.8005% (-689.89 +/- 72.54) (9062.94 -> 8373.04) page-faults:u: 2.3362% +/- 0.0384% (3701.00 +/- 60.83) (158421.00 -> 162122.00) cycles:u: -7.9589% +/- 0.8252% (-3031048897.60 +/- 314287122.04) (38083925666.10 -> 35052876768.50) instructions:u: -8.6432% +/- 0.0022% (-4010719175.80 +/- 1020253.35) (46402911564.20 -> 42392192388.40) branch-misses:u: -8.5667% +/- 3.3681% (-13392276.60 +/- 5265305.94) (156329178.70 -> 142936902.10) seconds time elapsed: -7.6092% +/- 0.7960% (-0.69 +/- 0.07) (9.07 -> 8.38) seconds user: -8.1069% +/- 0.8987% (-0.71 +/- 0.08) (8.74 -> 8.03) Comparing GC runtimes: Combined GC time: 1.4218% +/- 0.6146% (41.57 +/- 17.97) (2923.60 -> 2965.17) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot --no-lints --no-comments) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -13.2776% +/- 0.5461% (-2683.53 +/- 110.37) (20211.00 -> 17527.47) page-faults:u: -8.1957% +/- 0.0002% (-114963.50 +/- 2.25) (1402734.60 -> 1287771.10) cycles:u: -14.0568% +/- 0.5875% (-10861686217.90 +/- 453928594.78) (77270029416.60 -> 66408343198.70) instructions:u: -12.8518% +/- 0.0039% (-4120716309.30 +/- 1253748.99) (32063315038.40 -> 27942598729.10) branch-misses:u: -12.3483% +/- 4.9528% (-11819842.80 +/- 4740787.92) (95720172.60 -> 83900329.80) seconds time elapsed: -13.2848% +/- 0.5501% (-2.69 +/- 0.11) (20.23 -> 17.54) seconds user: -14.2010% +/- 0.8556% (-2.56 +/- 0.15) (18.00 -> 15.45) seconds sys: -5.7485% +/- 4.1202% (-0.13 +/- 0.09) (2.21 -> 2.08) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/analyzer/tool/stable_analysis.aot --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --sarguments="--no-warnings" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (stable_analysis.aot) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -17.0699% +/- 1.2566% (-1725.94 +/- 127.06) (10111.01 -> 8385.07) page-faults:u: -6.0303% +/- 0.0647% (-10406.40 +/- 111.60) (172567.50 -> 162161.10) cycles:u: -17.5229% +/- 1.3093% (-7452390822.40 +/- 556837791.41) (42529351599.20 -> 35076960776.80) instructions:u: -16.2915% +/- 0.0045% (-8250492166.60 +/- 2298292.70) (50642836187.30 -> 42392344020.70) branch-misses:u: -19.3893% +/- 5.0813% (-33703814.20 +/- 8832662.68) (173826494.90 -> 140122680.70) seconds time elapsed: -17.0646% +/- 1.2597% (-1.73 +/- 0.13) (10.12 -> 8.39) seconds user: -17.4043% +/- 1.3249% (-1.70 +/- 0.13) (9.77 -> 8.07) Comparing GC runtimes: Combined GC time: -9.6474% +/- 0.9303% (-317.80 +/- 30.65) (3294.17 -> 2976.37) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (stable_analysis.aot) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: -21.8650% +/- 0.3146% (-4909.91 +/- 70.64) (22455.59 -> 17545.68) page-faults:u: -12.8916% +/- 0.0001% (-190583.50 +/- 2.05) (1478355.30 -> 1287771.80) cycles:u: -23.1639% +/- 0.3324% (-20039621139.90 +/- 287545199.62) (86512110232.60 -> 66472489092.70) instructions:u: -21.0110% +/- 0.0045% (-7432530108.60 +/- 1594640.89) (35374475273.60 -> 27941945165.00) branch-misses:u: -20.4131% +/- 3.4484% (-21659250.80 +/- 3658856.19) (106104443.40 -> 84445192.60) seconds time elapsed: -21.8550% +/- 0.3165% (-4.91 +/- 0.07) (22.47 -> 17.56) seconds user: -22.9392% +/- 0.6813% (-4.61 +/- 0.14) (20.12 -> 15.50) seconds sys: -12.6236% +/- 4.3772% (-0.30 +/- 0.10) (2.34 -> 2.04) $ out/ReleaseX64/dart pkg/front_end/tool/benchmarker.dart --no-gc --silent --iterations=10 --gcs=3 --snapshot=pkg/front_end/tool/compile_files_in_folders.aot --snapshot=pkg/analyzer/tool/stable_analysis.aot --sarguments="--no-comments" --sarguments="--no-lints" --sarguments="--no-warnings" --arguments="/tmp/extracted_compile_dart_compile" Will now run 10+3 iterations with 2 snapshots. .........|.........|...... .......................... Comparing snapshot #1 (compile_files_in_folders.aot) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: 93.7631% +/- 1.7382% (4059.93 +/- 75.26) (4329.99 -> 8389.92) page-faults:u: 74.1975% +/- 0.0433% (69060.90 +/- 40.33) (93077.10 -> 162138.00) cycles:u: 95.0345% +/- 1.8170% (17109768118.30 +/- 327129529.20) (18003745305.70 -> 35113513424.00) instructions:u: 100.4940% +/- 0.0028% (21248236334.70 +/- 598466.90) (21143775631.70 -> 42392011966.40) branch-misses:u: 98.0546% +/- 7.7754% (70722114.60 +/- 5607995.68) (72125240.20 -> 142847354.80) seconds time elapsed: 93.7448% +/- 1.7272% (4.06 +/- 0.07) (4.33 -> 8.39) seconds user: 94.6406% +/- 1.9931% (3.93 +/- 0.08) (4.15 -> 8.08) seconds sys: 74.2391% +/- 13.9753% (0.13 +/- 0.03) (0.18 -> 0.32) Comparing GC runtimes: Combined GC time: 100.8652% +/- 2.6849% (1496.13 +/- 39.82) (1483.30 -> 2979.43) Will now run 10+0 iterations with 2 snapshots. Running with extra vm arguments: --new_gen_semi_initial_size=10000 --new_gen_semi_max_size=20000 .........|.........| .................... Comparing snapshot #1 (compile_files_in_folders.aot) with snapshot #2 (stable_analysis.aot --no-comments --no-lints --no-warnings) msec task-clock:u: 304.8456% +/- 1.7471% (13210.70 +/- 75.71) (4333.57 -> 17544.27) page-faults:u: 199.1590% +/- 0.0010% (857307.10 +/- 4.13) (430463.60 -> 1287770.70) cycles:u: 339.8369% +/- 2.0802% (51368129498.20 +/- 314431857.77) (15115522915.20 -> 66483652413.40) instructions:u: 121.8106% +/- 0.0124% (15344104830.80 +/- 1564723.39) (12596695878.50 -> 27940800709.30) branch-misses:u: 72.0768% +/- 6.0455% (35926587.50 +/- 3013368.88) (49844848.90 -> 85771436.40) seconds time elapsed: 304.7994% +/- 1.7436% (13.22 +/- 0.08) (4.34 -> 17.56) seconds user: 336.2468% +/- 1.5576% (11.94 +/- 0.06) (3.55 -> 15.49) seconds sys: 165.8816% +/- 7.6178% (1.28 +/- 0.06) (0.77 -> 2.05) ``` Change-Id: I048a6031e3d6bb56896fa28077b5e7ddf9add810 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/452783 Commit-Queue: Jens Johansen <jensj@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com> https://dart.googlesource.com/sdk/+/273fe8e63a6edba1a019d4a5861756e489506e6e
Monorepo is:
With depot_tools installed and on your path, create a directory for your monorepo checkout and run these commands to create a gclient solution in that directory:
mkdir monorepo cd monorepo gclient config --unmanaged https://dart.googlesource.com/monorepo gclient sync -D
This gives you a checkout in the monorepo directory that contains:
monorepo/ DEPS - the DEPS used for this gclient checkout commits.json - the pinned commits for Dart, flutter/engine, and flutter/flutter tools/ - scripts used to create monorepo DEPS engine/src/ - the flutter/buildroot repo flutter/ - the flutter/engine repo out/ - the build directory, where Flutter engine builds are created third_party/ - Flutter dependencies checked out by DEPS dart/ - the Dart SDK checkout. third_party - Dart dependencies, also used by Flutter flutter/ - the flutter/flutter repo
Flutter's instructions for building the engine are at Compiling the engine
They can be followed closely, with a few changes:
goma_ctl ensure_start is sufficient.Example build commands that work on linux:
MONOREPO_PATH=$PWD if [[ ! $PATH =~ (^|:)$MONOREPO_PATH/flutter/bin(:|$) ]]; then PATH=$MONOREPO_PATH/flutter/bin:$PATH fi export GOMA_DIR=$(dirname $(command -v gclient))/.cipd_bin goma_ctl ensure_start pushd engine/src flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk autoninja -C out/host_debug_unopt popd
The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.
For example, to build and run the Flutter spinning square sample on the web platform,
MONOREPO_PATH=$PWD cd flutter/examples/layers flutter --local-engine=host_debug_unopt \ -d chrome run widgets/spinning_square.dart cd $MONOREPO_PATH
To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command
flutter create --platforms=windows,macos,linux
on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter
Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:
MONOREPO_PATH=$PWD cd flutter/packages/flutter flutter test --local-engine=host_debug_unopt cd $MONOREPO_PATH
Please file an issue or email the dart-engprod team with any problems with or questions about using monorepo.
We will update this documentation to address them.
flutter commands may download the engine and Dart SDK files for the configured channel, even though they will be using the local engine and its SDK.gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.