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rdtsc: Binding for the rdtsc machine instruction

[ bsd3, foreign-binding, library ] [ Propose Tags ]

This module provides the function rdtsc for accessing the rdtsc machine register on modern IA-32 processors. This is a 64-bit counter which counts the number of processor cycles since the machine has been powered up. Using this instruction, you can make very precise time measurements which are independent of the actual CPU frequency. But note that you can get strange results sometimes on a superscalar processor.

Also note that the Haskell foreign function interface imposes some additional overheads. On my machine, it takes about 950 cycles to call this function twice and to compute the difference, whereas in C the overhead is only about 88 cycles.

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Versions [RSS] 1.1.1, 1.1.3, 1.1.3.1, 1.2.0.0, 1.3.0.0, 1.3.0.1
Dependencies base (>=4 && <5) [details]
License BSD-3-Clause
Author Martin Grabmueller <martin@grabmueller.de>
Maintainer martin@grabmueller.de
Category Foreign binding
Home page http://code.haskell.org/rdtsc
Source repo head: darcs get http://code.haskell.org/rdtsc/
Uploaded by MartinGrabmueller at 2012-03-15T21:41:53Z
Distributions LTSHaskell:1.3.0.1, NixOS:1.3.0.1, Stackage:1.3.0.1
Reverse Dependencies 6 direct, 4 indirect [details]
Downloads 5519 total (33 in the last 30 days)
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Readme for rdtsc-1.3.0.0

[back to package description] 
                                                              -*-outline-*-
* README file for Rdtsc binding

This small Cabal package provides a Haskell binding to the "rdtsc"
machine instruction on modern IA-32 processors.  This instruction can
be used to read the number of cycles since processor startup and gives
very accurate timing information.

---------------------------------------------------------------------------
Note: this package contains the file cycle.h by Matteo Frigo, which
provides access to cycle counters on several architectures.  The
license for this file is included in the file LICENSE in this package.
----------------------------------------------------------------------------

** Usage

Use

  runghc Setup.hs configure
  runghc Setup.hs build
  runghc Setup.hs install

for building and installing system-wide, or

  runghc Setup.hs configure --prefix=$HOME/haskell-modules
  runghc Setup.hs build
  runghc Setup.hs install --user

for building and installing in directory $HOME/haskell-modules.

Just import module "System.CPUTime.Rdtsc" into your Haskell file and use

  ghc --make FILENAME

to compile your program.

The "tests" directory contains a small test program for the module and
demonstrates its usage.  There is also a C version for this test
program, to test the overheads of Haskell's FFI.

Happy Haskell hacking,
  Martin