[Haskell-cafe] How to benckmark a Word64 -> Bool?

[Brandon Allbery]

On Wed, Feb 19, 2014 at 5:53 PM, Gregory Collins <greg at gregorycollins.net>wrote:

> This version is about 2x as fast as OP's on my system (look at h2.hs):
> https://gist.github.com/gregorycollins/9103248
>
> $  time ./dist/build/h1/h1 50000000 +RTS -A4M > /dev/null
> ./dist/build/h1/h1 50000000 +RTS -A4M > /dev/null  23.88s user 0.06s
> system 99% cpu 24.003 total
>
> $  time ./dist/build/h2/h2 50000000 +RTS -A4M > /dev/null
> ./dist/build/h2/h2 50000000 +RTS -A4M > /dev/null  13.57s user 0.09s
> system 99% cpu 13.706 total
>
> $  time ./dist/build/h3/h3 50000000 +RTS -A4M > /dev/null
> ./dist/build/h3/h3 50000000 +RTS -A4M > /dev/null  24.24s user 0.18s
> system 99% cpu 24.490 total
>
> The "system" number here is especially telling: this program is spending
> almost all of its time in syscalls.
>

You're reading it wrong. Using that last one:

24.2s on-CPU time in user mode
0.18s on-CPU time in system mode (kernel/syscalls)
99% of its total run time was actually spent on cpu (instead of, say, I/O
wait)
24.490 total run (wall) time

-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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