Add bench profiles to Cargo.toml to force codegen-units=1

This makes a small difference for NetworkGraph deserialization
as it enables more inlining across different files, hopefully
better matching user performance as well.

As of this commit, on an Intel 2687W v3, the serialization
benchmarks take:

test routing::network_graph::benches::read_network_graph  ... bench: 2,037,875,071 ns/iter (+/- 760,370)
test routing::network_graph::benches::write_network_graph ... bench: 320,561,557 ns/iter (+/- 176,343)

diff --git a/Cargo.toml b/Cargo.toml
index 597d4efbabb4e8cca00458db04ddfa2b3bb29c9c..df32ac5d9cf047ea597a75a0736de6f0a3537ce5 100644 (file)
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,3 +22,8 @@ panic = "abort"
 opt-level = 3
 lto = true
 panic = "abort"
+
+[profile.bench]
+opt-level = 3
+codegen-units = 1
+lto = true