|Fat references vindicated firstname.lastname@example.org (Jon Harrop) (2010-01-08)|
|Re: Fat references vindicated email@example.com (Kaz Kylheku) (2010-01-08)|
|Re: Fat references vindicated firstname.lastname@example.org (Jon Harrop) (2010-01-10)|
|From:||Jon Harrop <email@example.com>|
|Date:||Sun, 10 Jan 2010 05:43:38 +0000|
|Organization:||Flying Frog Consultancy Ltd.|
|Keywords:||interpreter, GC, performance|
|Posted-Date:||11 Jan 2010 10:52:46 EST|
Kaz Kylheku wrote:
> On 2010-01-08, Jon Harrop <firstname.lastname@example.org> wrote:
>> I just published some significant benchmark results:
> I don't see fat references being vindicated.
> The apparent winner of the benchmark is a C++ program running on a C++
> implementation that presumably does not use fat references.
On larger heaps with more (fat) references, HLVM beats all other garbage
collected language implementations and approaches the performance of C++.
That is a significant result.
> In the same blog entry above you do not argue about fat references,
> but rather that HLVM comes close to C++ because, like the C++ program,
> its inner loop computations are done with unboxed numbers. (Which is
> Use of unboxed numeric values, and use of fat references, are orthogonal
Yes. That aspect of the discussion was not related to this.
> Fat references merely make it /easy/ to implement unboxed numbers in
> the face of a garbage collector that is ignorant of static type.
> By using these fat references, you have built a ``four-lane highway'',
> which paves the way for all your ``wide loads'' like double-precision
> floats to travel anywhere that references can go. Any generic storage
> location that can hold a reference also has enough space to hold an
> unboxed number.
HLVM isn't storing numbers in fat references.
> You don't think benchmarks could be written which reveal performance
> disadvantages in fat references?
Good question. I can certainly construct contrived examples but I cannot
think of any realistic test that would suffer significantly from the use of
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
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