#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, | Phab:D1214 -------------------------------------+------------------------------------- Description changed by bgamari: Old description:

Now since GHC can produce useful debugging information (e.g. DWARF annotations and source notes) in compiled objects, it would great if we could leverage this for more efficient profiling.

While ideally we would be able to rely on external tools like `perf` for this task, this would require that the STG stack be walkable like a standard C stack.

A more feasible alternative is to incorporate a simple statistical profiler into the RTS.

New description: Now since GHC can produce useful debugging information (e.g. DWARF annotations and source notes) in compiled objects, it would great if we could leverage this for more efficient profiling. While ideally we would be able to rely on external tools like `perf` for this task, this would require that the STG stack be walkable like a standard C stack. A more feasible alternative is to incorporate a simple statistical profiler into the RTS. Profiling is defined loosely here as the collection of information describing the current state of evaluation in response to certain triggers. In practice this will be the collection of the current symbol being evaluated triggered on a few events of interest, * Memory allocation * Periodic timers for time-based profiling * Blackhole blocking for locating performance problems due to sharing in parallel programs -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, | Phab:D1214 -------------------------------------+------------------------------------- Changes (by rrnewton): * cc: rrnewton (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, Wiki Page: | Phab:D1214 -------------------------------------+------------------------------------- Comment (by bgamari): I didn't hear about this. It is currently quite possible to use just plain `perf` but it works relatively poorly while profiling Haskell code due various simplifications to the debug information which GHC must make to fit it into DWARF. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: patch Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, Wiki Page: | Phab:D1214 -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => patch -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: patch Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, Wiki Page: | Phab:D1214 -------------------------------------+------------------------------------- Changes (by bgamari): * milestone: 8.4.1 => 8.6.1 Comment: This won't happen for 8.4.1. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10915: Statistical profiling support in the RTS -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: feature request | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1215, Wiki Page: | Phab:D1214 -------------------------------------+------------------------------------- Changes (by domenkozar): * cc: domenkozar (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10915#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler