[racket] Gathering GC statistics for Racket programs

Looks neat. Can you add more statistics for gc time, like maximum/minimum/average/median?

On 10/01/2011 04:50 PM, Sam Tobin-Hochstadt wrote:
> Since Matthew added nice programmatic tools for understanding the
> behavior of the GC, I've written a little tool to summarize the GC
> behavior of your program.  You can find it on GitHub here:
> https://github.com/samth/gcstats .  To install it, do this:
>
> % git clone git://github.com/samth/gcstats.git
> % raco link gcstats
>
> Then you can do this:
>
> % racket -l gcstats -u my-program.rkt
>
> and you get output like this:
>
>      39,703,916 bytes allocated in the heap
>      28,890,688 bytes collected by GC
>      17,083,432 bytes max heap size
>      16,604,120 bytes max slop
>      28,229,632 bytes peak total memory use
>
> Generation 0:       5 collections,       32ms,    31.71ms elapsed
> Generation 1:       0 collections,        0ms,        0ms elapsed
>
> INIT  time       256 ms
> MUT   time       132 ms (    129.98 ms elapsed)
> GC    time        32 ms (     31.71 ms elapsed)
> TOTAL time       420 ms (    417.69 ms elapsed)
>
> %GC time       19.51%   ( 19.61% elapsed)
>
> Alloc rate     300,787,242 bytes per MUT second
>
> There are a few significant limitations at present:
> 1. There are a few GCs before the tool starts -- it can't report
> anything about them.
> 2. If you have multiple places, it will do totally the wrong thing.
> Fixing this will require a little more information from Racket.
> 3. The current architecture keeps too much info around during the run
> of the program.  I hope to fix that soon.
>
> The whole thing is inspired by the similar GHC reporting tools,
> documented here:
> http://www.haskell.org/ghc/docs/latest/html/users_guide/runtime-control.html#rts-options-gc
> .  The GHC tools report one more interesting piece of information,
> which is how many bytes are copied by the GC.  I hope we can get the
> information from the Racket GC at some point as well.