Jens Johansen
2849d34c7c
The RegEx engine in the VM was updated in
e443b89f23 which caused the analyzer
analyzing the CFE to use ~150 mio instructions more.
Part of this was an increased cost in ignore comment processing which
relied on regex. Using regex before the updated engine made
`processPrecedingComments` have a cost of ~240 mio instructions,
updating the regex engine took that to ~264 mio instructions.
This CL gets rid of the regex and takes the cost of
`processPrecedingComments` to ~74.4 mio instructions a saving of about
189 mio instructions (all then analyzing the CFE and looking at output
from `valgrind --tool=callgrind`).
Benchmarking with `perf stat` with normal GC gives:
```
task-clock:u: -2.1760% +/- 1.6063% (-265608341.80 +/- 196062087.98) (12206056036.20 -> 11940447694.40)
page-faults:u: 0.2301% +/- 0.0313% (448.20 +/- 60.88) (194764.60 -> 195212.80)
cycles:u: -2.2906% +/- 1.6090% (-1180119481.60 +/- 828994273.75) (51521138476.00 -> 50341018994.40)
instructions:u: -0.3325% +/- 0.0032% (-196547942.60 +/- 1874215.18) (59120651337.60 -> 58924103395.00)
seconds time elapsed: -2.1715% +/- 1.6011% (-0.27 +/- 0.20) (12.21 -> 11.95)
seconds user: -2.2487% +/- 1.7816% (-0.27 +/- 0.21) (11.87 -> 11.60)
Comparing GC data:
'No' GC change.
```
Note that it must push the GC - the savings isn't really 2% in time.
And with GC disabled:
```
instructions:u: -0.4562% +/- 0.0029% (-185499444.00 +/- 1189012.77) (40663084597.80 -> 40477585153.80)
```
So here a saving of ~185 mio which fits okay with the data from
valgrind.
Change-Id: Ib203baeac6a93f5e37c737080fed342dbd0740a7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/487021
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
analysis_server_plugin package
This package offers support for writing Dart analysis server plugins, for Dart 3.10 (Flutter 3.38) and later.
Analysis server plugins empower developers to contribute their own Dart static
analysis in IDEs and at the command line via dart analyze and flutter analyze. Analysis server plugins can offer the following static analyses:
- analysis rules, which report diagnostics in the IDE, and at the command line
- IDE quick fixes, which are local refactorings offered to users to correct a given diagnostic
- IDE quick assists, which are local refactorings that are offered at specific syntax nodes in code, but do not necessarily correct a static code issue
Review the following documents for how to write and how to use analysis server plugins: