flamelens is an interactive flamegraph viewer in the terminal.
Flamegraph tools such as FlameGraph and
inferno process output from various profiling tools and
generate intermediate data in the "folded" format ready for flamegraph plotting. Instead of plotting
the flamegraph as an SVG file, flamelens takes the folded stacks data and generate an interactive
flamegraph in the terminal.
No more hauling SVG files and opening a browser just to have a quick look at the profiling result!
Run flamelens with the filename of the profiling data in the form of "folded stacks":
flamelens <folded-stacks-filename>
You can also pipe data directly to flamelens without providing a filename.
You can use flamelens as the viewer of cargo flamegraph this way:
cargo flamegraph --post-process 'flamelens --echo' [other cargo flamegraph arguments]
The --echo flag ensures that the flamegraph SVG file is also generated by cargo flamegraph on
exit.
If have a perf.data file generated by perf (e.g. by using cargo flamegraph to profile your
program in Linux), you can visualize it in flamelens this way with the help of
inferno:
perf script -i perf.data | inferno-collapse-perf | flamelens
See inferno on generating folded stacks data from profiling data of different formats.
Display a live flamegraph of a running Python program using
py-spy as the profiler:
flamelens --pid <pid-of-python-program>
This requires enabling the python feature when installing.
Example of a live flamegraph
| Key | Action |
|---|---|
hjkl (or ← ↓ ↑→ ) |
Navigate cursor for frame selection |
f |
Scroll down |
b |
Scroll up |
G |
Scroll to bottom |
g |
Scroll to top |
Enter |
Zoom in on the selected frame |
Esc |
Reset zoom |
/<regex> |
Find and highlight frames matching the regex |
# |
Find and highlight frames matching the selected frame |
n |
Jump to next match |
N |
Jump to previous match |
r |
Reset to default view |
z (in Live mode) |
Freeze the flamegraph |
q (or Ctrl + c) |
Exit |
If you have Rust installed, flamelens is available on
crates.io and you can install it using:
cargo install flamelens --locked
If you want the live flamegraph functionality, install with the --all-features option:
cargo install flamelens --locked --all-features
Alternatively, build and install from source after cloning this repo:
cargo install --path $(pwd) --locked