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 Hernández-Novich (USB) <emhn@usb.ve>

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

                                          June 28, 2010                            THREADSCOPE(1)