performance measurement readme

pkg/analysis_server/benchmark/integration/README.md

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+# Running Benchmarks
+
+There are two entry points for running benchmarks:
+* **main.dart** - a general Dart application for running performance benchmarks
+* **local_runner.dart** - an example Dart application
+which sets up the local environment
+and then calls main.dart to run performance benchmarks
+
+## local_runner.dart
+
+This Dart application is one example for running performance benchmarks.
+When run, this application 1) extracts a branch from a git repository
+into a temporary directory, and 2) creates a symlink to the out or xcodebuild
+directory for proper package-root package resolution.
+The required command line arguments are
+* **gitDir** = a path to the git repository containing the initial target source
+* **branch** = the branch containing the initial target source
+* **inputFile** = the instrumentation or log file
+
+Once setup is complete, this applications calls main.dart
+
+## main.dart
+
+This Dart application reads an instrumentation or local log file produced by
+analysis server, "replays" that interaction with the analysis server,
+compares the notifications and responses with what was recorded in the log,
+and produces a report. It assumes that the environment for playback has
+already been setup.
+The required command line arguments are
+*  **-i, --input             <filePath>**
+The input file specifying how this client should interact with the server.
+If the input file name is "stdin", then the instructions are read from stdin.
+*  **-m, --map               <oldSrcPath>,<newSrcPath>**
+This option defines a mapping from the original source directory <oldSrcPath>
+when the instrumentation or log file was generated
+to the target source directory <newSrcPath> used during performance testing.
+Multiple mappings can be specified.
+WARNING: The contents of the target directory will be modified
+*  **-t, --tmpSrcDir         <dirPath>**
+The temporary directory containing source used during performance measurement.
+WARNING: The contents of the target directory will be modified
+*  **--newTaskModel**       enable the use of the new task model
+*  **-d, --diagnosticPort** localhost port on which server
+                            will provide diagnostic web pages
+*  **-v, --verbose**        Verbose logging
+*  **--vv**                 Extra verbose logging
+*  **-h, --help**           Print this help information