From 322478d9a238cee3292131840bfd5e7cdd617f41 Mon Sep 17 00:00:00 2001
From: Terts Diepraam <terts.diepraam@gmail.com>
Date: Mon, 26 Apr 2021 09:35:31 +0200
Subject: [PATCH] ls: document flamegraph

---
 src/uu/ls/BENCHMARKING.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/uu/ls/BENCHMARKING.md b/src/uu/ls/BENCHMARKING.md
index 84a0c3d84..c6568f879 100644
--- a/src/uu/ls/BENCHMARKING.md
+++ b/src/uu/ls/BENCHMARKING.md
@@ -32,3 +32,19 @@ This can also be used to compare with version of ls built before your changes to
 
 - Another thing to look at would be system calls count using strace (on linux) or equivalent on other operating systems.
 - Example: `strace -c target/release/coreutils ls -al -R tree`
+
+## Cargo Flamegraph
+
+With Cargo Flamegraph you can easily make a flamegraph of `ls`:
+```bash
+cargo flamegraph --cmd coreutils -- ls [additional parameters]
+```
+
+However, if the `-R` option is given, the output becomes pretty much useless due to recursion. We can fix this by merging all the direct recursive calls with `uniq`, below is a `bash` script that does this.
+```bash
+#!/bin/bash
+
+cargo build --release --no-default-features --features ls
+perf record target/release/coreutils ls "$@"
+perf script | uniq | inferno-collapse-perf | inferno-flamegraph > flamegraph.svg 
+```
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