NAME

       futhark-profile - profile Futhark programs

SYNOPSIS

       futhark profile JSONFILE

DESCRIPTION

       This  tool  produces  human-readable  profiling information based on information collected
       with futhark bench.  Futhark has only rudimentary support for profiling.  While the system
       can collect information about the run-time behaviour of the program, there is currently no
       automatic way to connect the  information  to  the  program  source  code.   However,  the
       collected information can still be useful for estimating the source of inefficiencies.

USAGE

       The  first  step  is  to  run  futhark  bench on your program, while passing --profile and
       --json. This will produce  a  JSON  file  containing  runtime  measurements,  as  well  as
       collected  profiling  information.  If  you  neglect  to  pass  --profile,  the  profiling
       information will be missing. The information in the JSON  file  is  complete,  but  it  is
       difficult for humans to read.

       The next step is to run futhark profile on the JSON file.  For a JSON file prog.json, this
       will create a top level  directory  prog.prof  that  contains  files  with  human-readable
       profiling information.  A set of files will be created for each benchmark dataset.  If the
       original invocation of futhark bench included multiple programs, then futhark profile will
       create subdirectories for each program (although all inside the same top level directory).

   Files produced
       Supposing a dataset foo, futhark profile will produce the following files in the top level
       directory.

       • foo.log: the running log produced during execution.  Contains many  details  on  dynamic
         behaviour, depending on the exact backend.

       • foo.summary: a summary of memory usage and cost centres.  For the GPU backends, the cost
         centres are kernel executions and memory copies.

       • foo.timeline: a list of all recorded profiling  events,  in  the  order  in  which  they
         occurred, along with their runtime and other available information

   Technicalities
       The  profiling  information,  including  the  log, is collected from a final run performed
       after all the measured runs.  Profiling information is not collected during the runs  that
       contribute  to  the  runtime  measurement  reported  by  futhark bench.  However, enabling
       profiling may still affect performance, as it  changes  the  behaviour  of  the  run  time
       system.

   Raw reports
       Alternatively,  the  JSON can also contain a raw profiling report as produced by the C API
       function futhark_context_report(). A directory is still created, but it will only  contain
       a single set of files, and it will not contain a log.

EXAMPLES

       This  shows the sequence of commands one might use to profile the program LocVolCalib.fut,
       which has three datasets associated with it, using the hip backend:

          $ futhark bench --backend=hip --profile --json result.json LocVolCalib.fut
          $ futhark profile result.json
          $ tree result.prof/
          result.prof/
          ├── LocVolCalib-data_large.in.log
          ├── LocVolCalib-data_large.in.summary
          ├── LocVolCalib-data_medium.in.log
          ├── LocVolCalib-data_medium.in.summary
          ├── LocVolCalib-data_small.in.log
          └── LocVolCalib-data_small.in.summary

BUGS

       Only the C-based backends currently support profiling.

       The c backend does not actually record useful profiling information.

SEE ALSO

       futhark-bench

COPYRIGHT

       2013-2024, DIKU, University of Copenhagen