doc: add instructions for coz in README

.gitignore

@@ -8,6 +8,7 @@ Cargo.lock
 .pre-commit-config.yaml
 .vscode
 **/*flamegraph*
+**/*.coz
 
 # Test coverage (grcov)
 default.profraw

README.md

@@ -151,3 +151,21 @@ cargo flamegraph --root -o path/to/wasm-flamegraph.svg --bench=plonk-benches --n
 # profile a specific test
 cargo flamegraph --root --unit-test -p jf-primitives -- pcs::univariate_kzg::tests::end_to_end_test
 ```
+
+You can also perform _causal profiling_ using [coz](https://github.com/plasma-umass/coz) only on Linux systems.
+
+``` bash
+# build the bench or example or binary that you want to profile
+cargo build --bench reed-solomon-coz --features profiling --release
+
+# you can find the binary inside ./target/<mode>/deps/<name>-<hash>
+coz run --- ./target/release/deps/reed_solomon_coz-db5107103a0e378c
+
+# plot your result
+coz plot
+
+# alternatively, view your profile.coz on https://plasma-umass.org/coz/
+```
+
+As an example, you can view `./primitives/src/reed_solomon_code/mod.rs::read_solomon_erasure_decode()` for some sample usages of `coz` annotation for latency profiling; view `./primitives/benches/reed_solomon_coz.rs` for the benchmark code.
+You could also conduct throughput profiling, read more [here](https://github.com/plasma-umass/coz/tree/master/rust).

primitives/benches/reed_solomon_coz.rs

@@ -7,7 +7,7 @@ const N: usize = 2048;
 const N_HALF: usize = 1024;
 // run it many times so coz will be triggered enough times
 // see: <https://github.com/plasma-umass/coz/issues/158#issuecomment-708507510>
-const ITERATIONS: usize = 2_000_000_000;
+const ITERATIONS: usize = 100;
 
 fn main() {
     coz::thread_init();