THREADSCOPE(1)						      General Commands Manual						    THREADSCOPE(1)

NAME

       threadscope - a graphical thread profiler for Haskell GHC programs

SYNOPSIS

       threadscope [program.eventlog]

DESCRIPTION

       Threadscope is a graphical thread profiler for Haskell programs.

       It  parses  and displays the content of .eventlog files emitted by the GHC 6.12.1 and later runtimes, showing a timeline of spark creation,
       spark-to-thread promotions and garbage collections.

       This helps debugging the parallel performance of Haskell programs, making easier to check that work is well balanced across  the  available
       processors and spot performance issues relating to garbage collection or poor load balancing.

ARGUMENTS

       threadscope  takes  the	name  of the GHC RTS event-log file to process as its single argument. If no filename is given, threadscope starts
       with an empty workspace, where any event-log file can be loaded by means of the GUI file browser facilities.

USAGE

       In order for threadscope to be useful, you have to compile your Haskell program to use GHC's threaded run-time and also to  create  runtime
       profile logs. This can be accomplished with the following command line options to ghc(1)

	   $ ghc -threaded -eventlog --make Foo.hs -o foo

       Once  the  program is built, execute it using the multithreaded run-time, specifying the number of HECs (Haskell Execution Contexts) to use
       in the usual manner, but also requesting the creation of an event log. For example, to use two HECs and create an event log you would use

	   $ foo +RTS -N2 -ls -RTS ...

       Once the program runs to completion, a file named foo.eventlog is produced. You can start threadscope from the  shell  prompt  passing  the
       event-log  filename  as	the single argument, or you can start threadscope from the desktop menus and use its file browsing capabilities to
       find and open it.

SEE ALSO

       ghc(1)

AUTHOR

       threadscope was written by

	   Simon Marlow <marlowsd@gmail.com>
	   Donnie Jones <donnie@darthik.com>
	   Satnam Singh <s.singh@ieee.org>

       This manual page was written by

	   Ernesto Hernandez-Novich (USB) <emhn@usb.ve>

       for the Debian project (and may be used by others).

								   June 28, 2010						    THREADSCOPE(1)