Rachelint commented on code in PR #12521: URL: https://github.com/apache/datafusion/pull/12521#discussion_r1765244595
########## docs/source/library-user-guide/profiling.md: ########## @@ -25,34 +25,44 @@ The section contains examples how to perform CPU profiling for Apache DataFusion ### Building a flamegraph -- [cargo-flamegraph](https://github.com/flamegraph-rs/flamegraph) +[Video: how to CPU profile DataFusion with a Flamegraph](https://youtu.be/2z11xtYw_xs) -Test: +A flamegraph is a visual representation of which functions are being run +You can create flamegraphs in many ways; The instructions below are for +[cargo-flamegraph](https://github.com/flamegraph-rs/flamegraph) which results +in images such as this: -```bash -CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph --root --unit-test datafusion -- dataframe::tests::test_array_agg + + +To create a flamegraph, you need to install the `flamegraph` tool: + +```shell +cargo install cargo-flamegraph ``` -Benchmark: +Then you can run the flamegraph tool with the `--` separator to pass arguments +to the binary you want to profile. -```bash -CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph --root --bench sql_planner -- --bench +Example: Flamegraph for `datafusion-cli` executing `q28.sql`. Note this +must be run as root on Mac OSx to access DTrace. + +```shell +sudo flamegraph -- datafusion-cli -f q28.sq ``` -Open `flamegraph.svg` file with the browser +You can also invoke the flamegraph tool with `cargo` to profile a specific test or benchmark. -- dtrace with DataFusion CLI +Example: Flamegraph for a specific test: ```bash -git clone https://github.com/brendangregg/FlameGraph.git /tmp/fg -cd datafusion-cli -CARGO_PROFILE_RELEASE_DEBUG=true cargo build --release -echo "select * from table;" >> test.sql -sudo dtrace -c './target/debug/datafusion-cli -f test.sql' -o out.stacks -n 'profile-997 /execname == "datafusion-cli"/ { @[ustack(100)] = count(); }' -/tmp/fg/FlameGraph/stackcollapse.pl out.stacks | /tmp/fg/FlameGraph/flamegraph.pl > flamegraph.svg +CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph --root --unit-test datafusion -- dataframe::tests::test_array_agg Review Comment: > I personally don't change the build settings when profiling -- it seems to work just fine for me OK, the setting may be not something matters. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
