Hi Celeste, You may already be aware, but there’s an alternative format to visualise profiles graphically. Instead of `-p`, use `-pj` to produce the profiling report in JSON format, and then load the resulting .prof file into speedscope.app <https://www.speedscope.app/>.
Cheers, Rodrigo Mesquita > On 30 Jul 2024, at 15:57, Celeste Hollenbeck <celeste.hollenb...@gmail.com> > wrote: > > Hi GHC Team, > > I have a question for a research project. I'm looking at GHC's profiler, and > the documentation says a profiling report displays "a break-down by cost > centre of the most costly functions in the program". Here's an example of the > report that I'm talking about: > > > MAIN MAIN 102 0 0.0 0.0 100.0 > 100.0 > CAF GHC.IO.Handle.FD 128 0 0.0 0.0 0.0 > 0.0 > CAF GHC.IO.Encoding.Iconv 120 0 0.0 0.0 0.0 > 0.0 > CAF GHC.Conc.Signal 110 0 0.0 0.0 0.0 > 0.0 > CAF Main 108 0 0.0 0.0 100.0 > 100.0 > main Main 204 1 0.0 0.0 100.0 > 100.0 > fib Main 205 2692537 100.0 100.0 100.0 > 100.0 > > This example is under Section 8.1 of the GHC User's Guide > https://downloads.haskell.org/ghc/latest/docs/users_guide/profiling.html#:~:text=GHC's%20profiling%20system%20assigns%20costs,to%20the%20enclosing%20cost%20centre. > > It looks like the numbers often add up to less than 100% for the %time, but I > don't see any documentation on a threshold for what makes a cost centre > "costly"—so I assume that "costly" means that it takes up any time > whatsoever, and any cost centres that take up any time at all are included in > the report? So perhaps the numbers under %time don't add up to 100% all the > time because of rounding error or perhaps garbage collection? Or something > else that is not profiled? > > Is that correct? > > Thanks, > > Celeste > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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