More CPU per execution than other functions, or that it is If aįunction's box is wider than others, that means that it consumes The width of each box shows the total time that thatįunction is on the CPU or is part of the call stack. With the functions that they call stacked on top of them, etc. The bottom, and the called functions will be stacked on top, When looking at aįlamegraph, the main function of your program will be closer to Of all stack samples that contained them. Then an SVG is generated showing theĬall stacks that were measured, widened to the proportion Processed and stacks that share common functions areĪdded together. Program are interrupted and the current location in yourĬode (based on the thread's instruction pointer) is recorded,Īlong with the chain of functions that were called to get there. The most permissive value is -1 but may notīe acceptable for your security needs etc.Įnv PERF= ~/bin/perf flamegraph /path/to/my/binary Systems Performance Work Guided By Flamegraphsįlamegraphs are used to visualize where time is being spent To an appropriate level for your environment. Lower the perf_event_paranoid value in proc To enable perf without running as root, you may Enabling perf for use by unprivileged users Viewers do not support interactive svg-files. Then open the resulting flamegraph.svg with a browser, because most image post-process Run a command to process the folded stacks, taking the input from stdin and outputting to stdout no-inline Disable inlining for perf script because of performance issues flamechart Produce a flame chart (sort by time, do not merge stacks) skip-after Cut off stack frames below may be repeated min-width Omit functions smaller than pixels reverse Generate stack-reversed flame graph i, -inverted Plot the flame graph up-side-down deterministic Colors are selected such that the color of a function does not change between runs c, -cmd Custom command for invoking perf/dtrace root Run with root privileges (using `sudo`) v, -verbose Print extra output to help debug problems For compatibility with `cargo run -release` no-default-features Disable default features unit-test Crate target to unit test, may be omitted if crate only has one target (currently profiles the test harness and all tests in the binary test selection can be passed as trailing arguments after `-` as separator) test Test binary to run (currently profiles the test harness and all tests in the binary) p, -package package with the binary to run profile Build with the specified profile Trailing arguments passed to the binary being profiled # Note that a separating `-` is necessary if `-unit-test` is the last flag.Ĭargo flamegraph -unit-test - test::in::package::with::single::crateĬargo flamegraph -unit-test crate_name - test::in::package::with::multiple:crateĬargo flamegraph -unit-test -dev test::may::omit::separator::if::unit::test::flag::not::last::flagįlamegraph is quite simple. # Note that the last -bench is required for `criterion 0.3` to run in benchmark mode, instead of test mode.Ĭargo flamegraph -bench some_benchmark -features some_features -bench`Ĭargo flamegraph -example some_example -features some_features # or anything else available via `perf list` or dtrace for your systemĬargo flamegraph -c "record -e branch-misses -c 100 -call-graph lbr -g" # this is handy for correlating things like branch-misses, cache-misses, # if you want to use interesting perf or dtrace options, use `-c` # if you want to pass arguments as you would with cargo run:Ĭargo flamegraph - my-command -my-arg my-value -m -f # if you'd like to profile a specific binary: # by default, `-release` profile is used, # defaults to profiling cargo run -release # cargo support provided through the cargo-flamegraph binary! # If you don't want this, you can pass -no-inline to flamegraph:įlamegraph -no-inline /path/to/my/binary -my-arg 5 # inlined at every stack frame for every sample. # NOTE: By default, perf tries to compute which functions are # or if the executable is already running, you can provide the PID via `-p` (or `-pid`) flag:įlamegraph -pid 1337 # if you'd like to profile an arbitrary executable:įlamegraph - /path/to/my/binary -my-arg 5
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