It will also depend on which math library and compiler options you use on the C side.
I’ll give you a bit of a warning though, if you are making decisions based solely on tests like this you you might be missing the bigger picture of the value of systems like Go. A simple example, even 1.5 sounds like a lot, as soon as you do any IO that will fall to about .0000001 percent difference. > On Feb 3, 2019, at 12:49 PM, Miki Tebeka <miki.teb...@gmail.com> wrote: > > Yup. Using int32 in Go reduces the difference to 1.5. Thanks > >> On Sunday, February 3, 2019 at 8:35:46 PM UTC+2, Robert Engels wrote: >> Also the go program is most likely using 64 bit math. Use int32 to compare >> it correctly. >> >>> On Feb 3, 2019, at 12:31 PM, Robert Engels <ren...@ix.netcom.com> wrote: >>> >>> Don’t use rtdsc in the C program use gettimeofday to ensure you are >>> comparing the same. >>> >>>> On Feb 3, 2019, at 12:22 PM, Miki Tebeka <miki....@gmail.com> wrote: >>>> >>>> Hi, >>>> >>>> I'm comparing two loops in Go and C. The Go code on my machine is about 3 >>>> times slower than C. I know C can be faster but didn't think it'll be that >>>> faster. Any ideas what's making the Go code slower? >>>> >>>> You can see the code at https://github.com/tebeka/go-c-loop >>>> >>>> Go Code: >>>> package main >>>> >>>> >>>> import ( >>>> "fmt" >>>> "os" >>>> "strconv" >>>> "time" >>>> ) >>>> >>>> >>>> func main() { >>>> n, _ := strconv.Atoi(os.Args[1]) >>>> m, _ := strconv.Atoi(os.Args[2]) >>>> >>>> >>>> sum := int(0) >>>> start := time.Now() >>>> for i := 0; i < 10000000; i++ { >>>> if i%n != m { >>>> sum += n >>>> } >>>> } >>>> >>>> >>>> fmt.Println(time.Now().Sub(start).Seconds(), sum) >>>> } >>>> >>>> >>>> >>>> C Code >>>> #include <stdio.h> >>>> #include <unistd.h> >>>> #include <x86intrin.h> >>>> >>>> >>>> >>>> >>>> int main(int argc,char** argv) { >>>> unsigned long long ull0,ull1; >>>> unsigned int sum=0,n,m; >>>> >>>> >>>> sscanf(argv[1],"%d",&n); >>>> sscanf(argv[2],"%d",&m); >>>> >>>> >>>> ull0 = __rdtsc(); >>>> for(int i=0; i<10000000; i++) { >>>> if(i%n != m) { >>>> sum += n; >>>> } >>>> >>>> >>>> } >>>> >>>> >>>> ull1 = __rdtsc(); >>>> printf("%f %d\n",(ull1-ull0)/2.1e9,sum); >>>> } >>>> >>>> >>>> >>>> -- >>>> 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...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>> -- >>> 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...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. > > -- > 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. -- 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.
