Prepare XPref ETL files for FlameGraph.

This node application parses a CSV file generated from an XPerf ETL file and produces a file that is ready to be consumed by flamegraph.pl.

See https://github.com/brendangregg/FlameGraph to get the flamegraph.pl and understand what a flame graph is.

The program can optionally also replace addresses in the stack frame with javascript symbols if the javascript compiler symbol information is in the CSV file.

Example usage

To capture stack traces:

1. xperf -on Latency -stackwalk profile
2. run the scenario you want to profile.
3. xperf -d perf.etl
4. SET _NT_SYMBOL_PATH=srvC:\symbolshttp://msdl.microsoft.com/downloads/symbols
5. xperf -i perf.etl -o perf.csv -symbols

To extract the stack for process x.exe and fold the stacks into perf.csv.fold:
node etlfold.js perf.csv x.exe

Then run the flamegraph script (requires perl) to generate the svg output:
flamegraph.pl perf.csv.fold > perf.svg

If the node ETW events for javascript symbols are available then the procedure becomes the following.

First ensure that the built-in node ETW provider is registered. Use wevtutil ep to check for 'NodeJS-ETW-provider'. If it is not available you may need to install a newer version of node. To manually register the manifest use 'wevtutil im node_etw_provider.man'

To capture stack traces:

1. xperf -start symbols -on NodeJS-ETW-provider -f symbols.etl -BufferSize 128
2. xperf -on Latency -stackwalk profile
3. run the scenario you want to profile.
4. xperf -d perf.etl
5. xperf -stop symbols
6. SET _NT_SYMBOL_PATH=srvC:\symbolshttp://msdl.microsoft.com/downloads/symbols
7. xperf -merge perf.etl symbols.etl perfsym.etl
8. xperf -i perfsym.etl -o perf.csv -symbols

The remaining steps are the same as in the previous example.

CONTRIBUTING

The source is available at:

https://github.com/MSOpenTech/ETWFlamegraph.git.

For issues, please use the Github issue tracker linked to the repository. Github pull requests are very welcome.