small framework for performance measurement and analysis

Version on this page:0.2.5
LTS Haskell 22.25:0.2.5
Stackage Nightly 2024-06-15:0.2.5
Latest on Hackage:0.2.5@rev:2

See all snapshots gauge appears in

BSD-3-Clause licensed by Bryan O'Sullivan
Maintained by Vincent Hanquez
This version can be pinned in stack with:gauge-0.2.5@sha256:8d60450bdec985c146d5632d4f5a8d60cec27d71ba6787ed1ee64d945d4c7c33,3923

Module documentation for 0.2.5

Used by 1 package in nightly-2024-02-26(full list with versions):

Gauge: a clone of criterion

This is a clone of criterion with a code / dependencies on a diet. It works the same way as criterion for outputing to terminal benchmark data.

features compared to criterion


  • JSON export
  • HTML/javascript pages
  • Glob benchmark matching


  • Small condensed output (-s or --small)
  • Raw measurements dumping (CSV)

Future Feature Plan

  • Remove further dependencies
  • storing benchmarks data in CSV and JSON
  • Add a standalone program taking benchmark data files and rendering to html/javascript/graphs
  • Make the library more useful as a standalone library to gather benchmark numbers related to functions in a programatic way

Small mode

It’s hard to compare many benchmarks with criterion, so gauge has a --small output:

identity                                 mean 41.65 ns  ( +- 2.246 ns  )
slow                                     mean 163.9 ns  ( +- 9.683 ns  )

Direct dependencies removed compared to criterion

Number of total dependencies (direct & indirect):

  • gauge: 12 dependencies
  • criterion: 63 dependencies

Dependencies removed:

  • Glob 0.8.0
  • abstract-deque 0.3
  • abstract-par 0.3.3
  • aeson
  • ansi-terminal
  • ansi-wl-pprint
  • array
  • attoparsec
  • base-compat 0.9.3
  • base-orphans 0.6
  • binary
  • blaze-builder
  • bytestring
  • cassava
  • cereal
  • code-page 0.1.3
  • containers
  • directory
  • dlist
  • erf
  • exceptions 0.8.3
  • filepath
  • ghc-boot-th 8.0.2
  • hashable
  • integer-gmp
  • integer-logarithms 1.0.2
  • js-flot 0.8.3
  • js-jquery 3.2.1
  • math-functions
  • microstache
  • monad-par
  • monad-par-extras 0.3.3
  • mtl 2.2.1
  • mwc-random
  • optparse-applicative
  • parallel
  • parsec 3.1.11
  • pretty
  • process
  • random 1.1
  • scientific
  • statistics
  • stm
  • tagged 0.8.5
  • template-haskell
  • text
  • time
  • time-locale-compat
  • transformers-compat
  • unix
  • unordered-containers
  • uuid-types 1.0.3
  • vector-algorithms
  • vector-binary-instances
  • vector-th-unbox

Criterion graph of dependencies:


Gauge graph of dependencies:




  • Add GHCJS support (statistical analysis is not supported)
  • Fix issue with perRunEnv
  • Drop support for GHC 7.8


  • Enhancement: Add nfAppIO and whnfAppIO functions, which take a function and its argument separately like nf/whnf, but whose function returns IO like nfIO/whnfIO. This is useful for benchmarking functions in which the bulk of the work is not bound by IO, but by pure computations that might otherwise be optimized away if the argument is known statically.

  • Bug Fix: Pass -m exact option to the child processes used to run benchmarks in an isolated manner. This avoids running a wrong benchmark due to the default prefix match.


  • Add a new benchmark matching option “-m exact” to match the benchmark name exactly.


  • Write data to CSV file in quick mode too.
  • Fix the CSV file header to match with the data rows for the --csvraw case.
  • Fix issue with GC metrics in 32 bits that would silently wrap and failure in optional machinery.
  • Simplify dependencies in tests using foudation checks.


  • Inline math-functions & mwc-random:
    • Remove most functions, instances and types, that are unnecessary for gauge
    • Remove unsafe seeding with partial seed (unused in gauge anyway)
    • Remove vector-th-unbox dependency (transitively template-haskell, pretty, ghc-boot-th)
    • Remove time dependency
  • Re-add Gauge.Benchmark to Gauge.Main to keep the transition between criterion and gauge easy
  • Fix cycles reporting on linux, osx and windows
  • Add some extra callstack for reporting on partial function
  • Fix compilation with Semigroup => Monoid (compilation on 8.4). still unsupported
  • Add some color on terminal output


  • Usability: Simplify and organize the documentation and user APIs.
  • Functionality:
    • Add measurement and reporting of more performance counters on Unices (collected via getrusage) for example page faults, user time, system time and rss are now available in verbose mode.
    • Re-enable CSV analysis with the same output format as criterion (--csv)
    • Add CSV measurement dumping with --csvraw
  • Control: Provide better control over measurement process with --min-samples, --min-duration and --include-first-iter flags.
  • Speed: Add --quick flag that provides results much faster (10x) without using statistical analysis.
  • Reliability:
    • Fix a bug in GC stats collection and reporting with GHC 8.2 that caused incorrect reporting of some GC stats.
    • Fix a bug in statistical regression that caused incorrect reporting of mean and other stats.
    • Improve reliability by isolating benchmarks from one another using the --measure-with flag. The results of one benchmark are no longer affected by other benchmarks because each benchmark runs in a separate process.
    • Introduce an optional value type Optional with an efficient runtime representation to replace the ad-hoc fromXXX functions and the untyped approach.
  • Modularity:
    • Introduce --measure-only flag that allows just measurement and no analysis or reporting.
    • Provide modular build, measurement code is cleanly separated from statistical analysis code. As a result a leaner version can now be built without analysis code (controlled by the analysis build flag).
    • Clean, refactor & rewrite source code
  • Remove code-page dependency


  • Simplify monad handling, remove foundation as dependency


  • condensed display with --small


  • remove optparse-applicative


  • remove bunch of dependencies
  • initial import of criterion-