Joseph D. Darcy
joe.darcy at oracle.com
Tue May 9 01:09:06 UTC 2017
To strengthen Brian' point, running faster on at least one platform is a
necessary but not sufficient condition for a change like this since it
is possible the change could run slower on a different platform. To
guard against that being the case, with data points across more
platforms a better informed decision can be made.
Unfortunately, to my knowledge there isn't a convenient way to run a
test like this across a large set of platforms of interest.
On 5/8/2017 6:01 PM, Brian Burkhalter wrote:
> Thanks for running the numbers.
> On May 8, 2017, at 5:42 PM, Isaac Levy <isaac.r.levy at gmail.com
> <mailto:isaac.r.levy at gmail.com>> wrote:
>> bitCountInt avgt 10 44550.630 ± 2670.294 ns/op
> [41880, 47221]
>> bitCountIntNew avgt 10 33904.058 ± 1108.438 ns/op
> [32796, 35012]
>> bitCountLong avgt 10 58638.138 ± 3736.014 ns/op
> [54902, 62374]
>> bitCountLongNew avgt 10 38700.601 ± 526.648 ns/op
> [38174, 39227]
> So the ranges don’t overlap which is important.
>> JDK 1.8.0_131, 2.3ghz Core i7, each run counting numbers 0 to 2^14
> Thing is one needs to run the benchmark on a variety of hardware. I
> went through a lot of this sort of thing myself when evaluating among
> other things for example the crossover thresholds for the Karatsuba
> and Toom-Cook multiplication algorithms in BigInteger multiplication.
> There was a lot of variation.
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