Fuel Core Benches

This directory contains a set of benchmarks for Fuel Core. The benchmarks are used for calculating gas metering costs for the Fuel Core VM.

Running the benchmarks

To run the benchmarks, you can use cargo bench -p fuel-core-benches command available. Alternatively you can use cargo criterion -p fuel-core-benches if you have it installed. For more information on using criterion see the guide.

Profiling a benchmark

Sometimes it is useful to produce a flamegraph from a benchmark to verify you are measuring the correct things. To do this you can use the cargo flamegraph command.

Benchmarking a specific function

First build the benchmark with debug symbols: CARGO_PROFILE_RELEASE_DEBUG=true cargo-criterion -p fuel-core-benches --no-run Then you need to find the actual test binary that was built: ls target/release/deps/vm* -lat | head -1 Should give you something like: target/release/deps/vm-a17190f2ca5e7169 Then you can run the benchmark with the flamegraph command (runs the bench for 10 seconds): flamegraph target/release/deps/vm-a17190f2ca5e7169 --bench bench_name --profile-time 10 For example if you want to profile the swwq op you would do (it's regex): flamegraph target/release/deps/vm-a17190f2ca5e7169 --bench '^swwq/swwq$' --profile-time 10 Or for a dependent bench you would do: flamegraph target/release/deps/vm-a17190f2ca5e7169 --bench '^srwq/100$' --profile-time 10

Using collect to generate bench data

Firstly you should run the benchmarks and collect the output: cargo criterion -p fuel-core-benches --message-format json -- --bench >bench.json You could just pipe the output into the collect binary but benches are slow to run so I suggest saving the output like above.

Then you can run the collect binary to generate the data you want: cargo run -p fuel-core-benches --bin collect --release -- --input bench.json This will generate a gas-costs.yaml file in the current directory like:

burn: 35
call:
  base: 311
  dep_per_unit: 14

There are multiple output options. See collect --help for more information.

Generating the fuel-vm default-gas-costs.rs

Do the same as above except run the following collect command. cargo run -p fuel-core-benches --bin collect --release -- --input bench.json -f rust --output default-gas-costs.rs This will generate a default-gas-costs.rs file in the current directory like:

This file can then replace the one in fuel-vm/src/gas/default-gas-costs.rs.