Tu cast pola s ktorou pracujes mas v L1/ L2 cache. V momente ked pristupujes k inej casti pola ktora je niekolko megabajtov vzdialena tak procesor musi natiahnut tie udaje z ram do cache. Neviem presne cisla ale trva to zhruba tych 300 strojovych cyklov . Vypadok L2 neviem kolko trva, je to v manualoch.
On Wednesday, August 3, 2016 at 4:24:08 PM UTC+2, ondrej...@gmail.com wrote: > > Downgrading to 1.6.3, I'm also getting consistent benchmark results. I'll > try 1.7 on my Mac at home later today, to see if it's a 1.7 thing or a > Windows thing or...? > > On Wednesday, 3 August 2016 14:55:20 UTC+1, C Banning wrote: >> >> PS - that's with Go v1.6. >> >> On Wednesday, August 3, 2016 at 7:49:49 AM UTC-6, C Banning wrote: >>> >>> On MacBook Pro, 2.6 GHz Intel Core i7, 8 GB 1600 MHz memory, running OS >>> X 10.11.6, your benchmarks look pretty consistent: >>> >>> >>> BenchmarkStart-4 2000000000 1.45 ns/op >>> >>> BenchmarkEnd-4 2000000000 1.47 ns/op >>> >>> BenchmarkHereThere-4 2000000000 1.46 ns/op >>> >>> BenchmarkStartEnd-4 2000000000 1.46 ns/op >>> >>> BenchmarkEndStart-4 2000000000 1.46 ns/op >>> >>> BenchmarkFirst-4 2000000000 0.59 ns/op >>> >>> BenchmarkSecond-4 2000000000 0.59 ns/op >>> >>> BenchmarkLast-4 2000000000 0.59 ns/op >>> >>> BenchmarkPenultimate-4 2000000000 0.58 ns/op >>> >>> On Wednesday, August 3, 2016 at 5:56:32 AM UTC-6, Ondrej wrote: >>>> >>>> I wanted to see if there was a difference when loading values from a >>>> large-ish slice (10000 elements) - to see if caches, locality and other >>>> things had any meaningful impacts. Whilst individual value loading (just a >>>> single element) seemed to be equally fast regardless of element position >>>> (see bench of First, Second, Last, Penultimate), when combining loading of >>>> various values, there seem to be almost a 2.5x difference between loading >>>> first four values and loading last four values (first two benchmarks). >>>> Loading the same values, just in different order, also yields different >>>> execution times. But alternating loading (0, n, 1, n-1) seems to be faster >>>> than loading first two values and last two values. >>>> >>>> (Setting the test slice to be an array instead wipes all differences >>>> between benchmarks.) >>>> >>>> Can anyone point me to a resource - be it Go specific or on computer >>>> science principles - that would explain these large differences? >>>> >>>> Thanks! >>>> >>>> https://play.golang.org/p/oMqDvXI9YW >>>> >>> -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
