No, I'm talking about the two for loops. I'd expect that if you want to transfer large amounts of data back and forth, you'll get better results by using typed arrays.
On Tue, Oct 25, 2016 at 7:10 AM Samantha Krieger <[email protected]> wrote: > Thanks for responding! > > OK I assume you're talking about the overhead associated largely with > these lines: > > Isolate* isolate = Isolate::GetCurrent(); > HandleScope scope(isolate); > > if (args.Length() < 1 || !args[0]->IsArray()) { > isolate->ThrowException( > Exception::TypeError( > String::NewFromUtf8(isolate, > "First argument should be an array"))); > return; > } > > Handle<Array> arr = Handle<Array>::Cast(args[0]); > > .... > > > If that is the case: > > 1) Wouldn't the overhead get amortized with larger array size? (Presumably > the answer is no so why not?) > 2) Is there anything I can do to minimize that overhead? It was my > understanding that using Isolates and Handle Scopes are a part of the > necessary boiler plate. Can they be avoided? > (3) What about them causes so much overhead if they are the ones > responsible?) > > Really appreciate all the help!!!! Thanks so much again! > > On Monday, October 24, 2016 at 3:42:00 AM UTC-4, Jochen Eisinger wrote: > > compared to the JS function, the C implementation has a lot of overhead to > copy the data back and forth, so it's not surprising that this overhead > shows up especially on larger arrays > > On Mon, Oct 24, 2016 at 2:47 AM Samantha Krieger <[email protected]> > wrote: > > Just wondering if I'm crazy/doing something incredibly stupid. > > I wrote this sort function using v8 (wrapper around qsort): > > void Sort(const FunctionCallbackInfo<Value>& args) { > Isolate* isolate = Isolate::GetCurrent(); > HandleScope scope(isolate); > > if (args.Length() < 1 || !args[0]->IsArray()) { > isolate->ThrowException( > Exception::TypeError( > String::NewFromUtf8(isolate, > "First argument should be an array"))); > return; > } > > Handle<Array> arr = Handle<Array>::Cast(args[0]); > int size = arr->Length(); > double other_arr[size]; > for (int i = 0; i < size; i++){ > other_arr[i] = arr->Get(i)->NumberValue(); > } > > > qsort(other_arr, size, sizeof(other_arr[0]), compare); > Handle<Array> res = Array::New(isolate, size); > for (int i = 0; i < size; ++i) { > // printf ("I val: %f\n",other_arr[i]); > res->Set(i, Number::New(isolate, other_arr[i])); > } > > args.GetReturnValue().Set(res); > > } > > > > when i run it in js from node, its markedly slower than the equivalent js > sort (which I understand v8 [].sort() uses qsort under the hood) for objects > between 1000 - 10000+ > > > var sort = require('bindings')('sort.node'); > > > function benchmarkSort(size){ > > var arr = helpers.generateArray(size); > var cres = benchmark(sort.sort, [arr], 10); > > > var arr = helpers.generateArray(size); > var jsres = benchmark(helpers.sort, [arr], 10); > return { > c: cres, > js: jsres > }; > > } > > > function benchmark(fn, args, times){ > var noTimes = (typeof times != 'undefined'? times: NO_TIMES); > var start = Date.now(); > var result = run(fn, noTimes, args); > var duration = Date.now() - start; > return duration; > } > > > ----- Cost for sorting 100 ------- > JS time: 1 msec > C time: 1 msec > ----- Cost for sorting 1000 ------- > JS time: 4 msec > C time: 3 msec > ----- Cost for sorting 10000 ------- > JS time: 22 msec > C time: 37 msec > ----- Cost for sorting 100000 ------- > JS time: 278 msec > C time: 441 msec > > > These results seem incredibly strange. Am I doing something incredibly > stupid/missing something? Can someone explain whats going on? Much > appreciated!!!! > > -- > -- > v8-dev mailing list > > [email protected] > > > http://groups.google.com/group/v8-dev > --- > You received this message because you are subscribed to the Google Groups > "v8-dev" group. > > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > > > For more options, visit https://groups.google.com/d/optout. > > -- > -- > v8-dev mailing list > [email protected] > http://groups.google.com/group/v8-dev > --- > You received this message because you are subscribed to the Google Groups > "v8-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
