GHC's -fprof-auto does not work with LINE pragmas
Please note the difference between the two .prof files created. The "profnopragma" one contains a "main" and the "profpragma" one doesn't. I came across this problem profiling a much larger source. In that case, ghc failed to profile anything within my source code at all!
[timothy@timothy haskell]$ cat profpragma.hs
f="hi"{-# LINE 1 "hi.hs" #-}
main :: IO (){-# LINE 2 "hi.hs" #-}
main = print f{-# LINE 3 "hi.hs" #-}
[timothy@timothy haskell]$ cat profnopragma.hs
f="hi"
main :: IO ()
main = print f
[timothy@timothy haskell]$ ghc profpragma.hs -prof -fprof-auto
[timothy@timothy haskell]$ ghc profnopragma.hs -prof -fprof-auto
[timothy@timothy haskell]$ ./profpragma +RTS -p
"hi"
[timothy@timothy haskell]$ ./profnopragma +RTS -p
"hi"
[timothy@timothy haskell]$ cat profpragma.prof
Sun Aug 26 20:30 2012 Time and Allocation Profiling Report (Final)
profpragma +RTS -p -RTS
total time = 0.00 secs (0 ticks @ 1000 us, 1 processor)
total alloc = 49,704 bytes (excludes profiling overheads)
COST CENTRE MODULE %time %alloc
CAF GHC.IO.Encoding 0.0 5.6
CAF GHC.IO.Handle.FD 0.0 69.8
CAF GHC.Conc.Signal 0.0 1.4
CAF Main 0.0 21.7
individual inherited
COST CENTRE MODULE no. entries %time %alloc %time %alloc
MAIN MAIN 46 0 0.0 0.7 0.0 100.0
CAF Main 91 0 0.0 21.7 0.0 22.1
f Main 92 1 0.0 0.3 0.0 0.3
CAF GHC.Conc.Signal 87 0 0.0 1.4 0.0 1.4
CAF GHC.IO.Handle.FD 85 0 0.0 69.8 0.0 69.8
CAF GHC.IO.Encoding 80 0 0.0 5.6 0.0 5.6
CAF GHC.IO.Encoding.Iconv 66 0 0.0 0.5 0.0 0.5
[timothy@timothy haskell]$ cat profnopragma.prof
Sun Aug 26 20:30 2012 Time and Allocation Profiling Report (Final)
profnopragma +RTS -p -RTS
total time = 0.00 secs (0 ticks @ 1000 us, 1 processor)
total alloc = 49,704 bytes (excludes profiling overheads)
COST CENTRE MODULE %time %alloc
CAF GHC.IO.Encoding 0.0 5.6
CAF GHC.IO.Handle.FD 0.0 69.8
CAF GHC.Conc.Signal 0.0 1.4
main Main 0.0 20.8
individual inherited
COST CENTRE MODULE no. entries %time %alloc %time %alloc
MAIN MAIN 46 0 0.0 0.7 0.0 100.0
CAF Main 91 0 0.0 0.9 0.0 22.1
f Main 93 1 0.0 0.3 0.0 0.3
main Main 92 1 0.0 20.8 0.0 20.8
CAF GHC.Conc.Signal 87 0 0.0 1.4 0.0 1.4
CAF GHC.IO.Handle.FD 85 0 0.0 69.8 0.0 69.8
CAF GHC.IO.Encoding 80 0 0.0 5.6 0.0 5.6
CAF GHC.IO.Encoding.Iconv 66 0 0.0 0.5 0.0 0.5
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.4.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |