Benchmark a Haskell development system

Benchmark results

CPU	building GHC 9.12.4 with --flavour=quickest
Intel Core Ultra 7 270K Plus	(no results yet)
Intel Core Ultra 7 255H	(no results yet)
Intel Core Ultra 7 258V	(no results yet)
Intel Core i9-10900K	526s (8m 46s)
Intel Core i7-1165G7	715s (11m 55s)
Intel Core 2 Duo P8700	3013s (50m 13s)

About

ghc-bench measures how well a system performs on Haskell development workloads compared to other systems.

It allows you to:

• benchmark a system
• submit benchmark results via GitHub issues
• compare benchmark results across systems

This can be used to:

• verify that a system delivers expected performance
• understand the impact of a hardware upgrade
• guide purchasing decisions

Running ghc-bench

Requirements:

• cabal
• ghc-9.12.4
• ghc-bench

If all of these are on your PATH you can benchmark your system with:

$ ghc-bench

If you need detailed instructions for ghcup or stack then read on.

Running ghc-bench with ghcup

Install cabal, ghc-9.12.4, and ghc-bench:

$ ghcup install cabal
$ ghcup install ghc 9.12.4 --no-set
$ cabal update && cabal install -w ghc-9.12.4 ghc-bench

Run ghc-bench:

$ ghc-bench

Running ghc-bench with stack

Install cabal and ghc-bench:

$ stack --resolver=nightly-2026-04-11 install cabal-install
$ cabal update && stack --resolver=nightly-2026-04-11 exec -- env --unset=GHC_PACKAGE_PATH cabal install ghc-bench

Run ghc-bench:

$ stack --resolver=nightly-2026-04-11 exec -- env --unset=GHC_PACKAGE_PATH ghc-bench

Details

Running ghc-bench requires ~3.4G free space in /tmp/.

• ghc-bench creates a separate temporary directory for each benchmark run under /tmp/ghc-bench and always cleans up after itself.
• The GHC 9.12.4 source tarball is stored at /tmp/ghc-bench/ghc-9.12.4-src.tar.gz and reused between benchmark runs (and users).
• cabal is used to build Hadrian (the GHC build system)
  • any missing Hadrian dependencies are installed to ~/.local/state/cabal/store; this is the only situation where running ghc-bench may modify anything outside of /tmp/ghc-bench

Exact steps performed by ghc-bench:

1. Download the GHC 9.12.4 source tarball to /tmp/ghc-bench/ghc-9.12.4-src.tar.gz
2. Unpack GHC sources into a temporary directory under /tmp/ghc-bench
3. Set the environment variable GHC to the absolute path of ghc-9.12.4
4. Run ./configure
5. Build Hadrian (not measured as part of the benchmark) by invoking hadrian/build --help to trigger dependency compilation
6. Run hadrian/build -j$(nproc) --flavour=quickest