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performance: double.toString #17622

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DartBot opened this issue Mar 19, 2014 · 4 comments
Open

performance: double.toString #17622

DartBot opened this issue Mar 19, 2014 · 4 comments
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area-vm Use area-vm for VM related issues, including code coverage, FFI, and the AOT and JIT backends. type-performance Issue relates to performance or code size

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@DartBot
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DartBot commented Mar 19, 2014

This issue was originally filed by @tatumizer

I will start submitting performance issues gradually, following reply from Srdjan and Peter.

calling 123456.toString() takes 28 nanoseconds (very good! improved by a factor of 3 in the last release!)
calling 123456.0.toString() takes 330 nanoseconds. In V8 javascript, same conversion takes 80 nanoseconds.
@DartBot
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DartBot commented Mar 19, 2014

This comment was originally written by @tatumizer

probably, comparison above is not quite valid (in JS, ints are doubles and 123456.0 is the same as 123456), so it's better compare conversion of 12345.6 - then we have: in dart: 340 ns; in javascript: 270 ns.

@floitschG
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It might be worth it to test if the double-input is an integer in a specific range to get the fast double->string for doubles with integer values.

The double->string library is pretty much the same in Dart and v8. It should be possible to optimize the 340ns.

Added Area-VM, Triaged labels.

@DartBot
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DartBot commented Mar 19, 2014

This comment was originally written by @tatumizer

Tested java: it has special case for doubles with int values, too: converting 123456.1 takes 250 ns, but 123456.0 is faster: 150 ns. Tested on the same machine as dart, so the benchmarks are good for reference.

@DartBot
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DartBot commented Mar 19, 2014

This comment was originally written by @tatumizer

Looks like current dart implementation of int.toString() is faster than java by 30-35%, and on par with best C++ ones.
It would be good to leverage this code while converting double (if possible).

@DartBot DartBot added Type-Defect area-vm Use area-vm for VM related issues, including code coverage, FFI, and the AOT and JIT backends. labels Mar 19, 2014
@kevmoo kevmoo added type-bug Incorrect behavior (everything from a crash to more subtle misbehavior) and removed priority-unassigned labels Feb 29, 2016
@zanderso zanderso added type-performance Issue relates to performance or code size and removed type-bug Incorrect behavior (everything from a crash to more subtle misbehavior) labels Jun 23, 2016
@joshualitt joshualitt mentioned this issue May 9, 2017
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area-vm Use area-vm for VM related issues, including code coverage, FFI, and the AOT and JIT backends. type-performance Issue relates to performance or code size
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double::toString perf improvement for integer case joshualitt/sdk
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@kevmoo @zanderso @floitschG @DartBot