Benchmarks

[keith]

This issue just adds some more detailas about the benchmarks in the readme so I can remember how to reproduce them in the future, or if someone else wants to check my work.

Here is the top level graph:

More details:

All benchmarks were performed on a M1 Max MacBook Pro with 64gbs of ram running macOS 12.1.

ld64: 711 bundled with Xcode 13.2.1
zld: 1.3.3
lld: built locally from this commit

envoy was built on this commit with bazel 4.2.1 by running bazel build envoy --spawn_strategy=standalone --profile=trace.json --experimental_generate_json_trace_profile and modifying source/exe/BUILD to add linkopts = ["--ld-path=..."] avoiding --linkopt to not thrash rules_foreign_cc repositories.

clang was built on this commit using cmake ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS='clang' -DCMAKE_BUILD_TYPE=Debug -DLLVM_USE_LINKER=/tmp/linker.sh where linker.sh exec'd lld and output the command for easy re-running.

alacritty was built on this commit using cargo 1.58 and RUSTFLAGS="-C link-args=--ld-path=..." cargo build -Z timings