[MLton] latest benchmarks

[Matthew Fluet]

Jesper Louis Andersen wrote:
> Hmm, it failed the -codegen native as well as -codegen amd64. I'll
> investigate further.

For mlton-20051205 (on x86 or x86_64), -codegen native implies using the 
x86 codegen.

For mlton.svn.trunk, -codegen native has been eliminated.
On x86, -codegen x86 implies using the x86 codegen.
On amd64, -codegen amd64 implies using the amd64 codegen.

It would be easy to restore the -codegen native option on 
mlton.svn.trunk and choose the appropriate native codegen for the 
architecture.

> On 6/21/07, Jesper Louis Andersen <jesper.louis.andersen at gmail.com> wrote:
>>
>> I have a 32bit FreeBSD compile ready. Benchmarks to trickle in tomorrow
>> when I
>> get it to crunch while at work (It takes a fair amount of time for it to
>> finish and I don't
>> want to mess too much with the laptop while it processes the benchmarks).
>>
>> There are also a few tweaks needed to run on 64-bit FreeBSD. I hope to be
>> able to
>> look into them around the 1st of July.
>>
>> On 6/20/07, Matthew Fluet <fluet at tti-c.org> wrote:
>> >
>> > I've merged the x86_64 branch into trunk.  Since the previous
>> > announcement of the experimental release, there were only two minor 
>> bugs
>> > reported:
>> >   1) Bug with -align 8 on x86_64
>> >   2) Inconsistent behavior with -const 'MLton.detectOverflow false'
>> > These have both been fixed, and I'm pretty happy with the state of the
>> > x86_64 port.
>> >
>> > I ran the benchmark suite to compare the last public release to the
>> > current trunk.  It is a bit of an apples-to-oranges comparison, since I
>> > ran the benchmarks on an AMD Opteron (64-bit) system.  So, the 20051205
>> > compiler (and its resulting executables) are running in 32-bit mode,
>> > while the trunk compiler (and its resulting executables) are running in
>> > 64-bit mode.
>> >
>> > [BTW, it would be nice if someone could run a corresponding benchmark
>> > suite on a 32-bit system, for a more apples-to-apples comparison.]
>> >
>> > You can see all of the results at:
>> >
>> > 
>> http://mlton.org/cgi-bin/viewsvn.cgi/*checkout*/mlton/trunk/doc/x86_64-port-notes/bench-20070619.txt?rev=5659 
>>
>> >
>> > Some of the highlights:
>> >
>> > * Benchmarks were run on a uni-core, dual-processor AMD Opteron 
>> 2.0GHz ,
>> > 8GB Memory, Fedora Core 6 machine (with gcc version 4.1.1 and linux
>> > version 2.6.20 (x86_64)).
>> >
>> > * compile time and code size is up across the board on trunk vs
>> > 20051205.  I suspect that part of the code size increase can be
>> > attributed to the comparison of 32-bit executables to 64-bit
>> > executables.  Any 64-bit operation requires an additional 8bit
>> > instruction prefix (as do 32-bit ops that touch the extended register
>> > set).  Compile time is probably partly explained by the bigger Basis
>> > Library implementation (increasing elaboration time and carrying more
>> > code through early optimizations), and partly by the fact that the 
>> trunk
>> > compiler is executing a little slower than the 20051205 compiler.
>> >
>> > * recent versions of gcc are doing fairly well with the C code.  (Note
>> > that using -codegen c with 20051205 uses the version of gcc on the host
>> > machine.)  Indeed, the flat-array.sml benchmark needs to be revised, as
>> > gcc recognizes that the inner loop is pure (Overflow exceptions are
>> > handled within the loop) and unused.  The SSA{,2} optimizer should also
>> > discover that the loop may be optimized, but that is another issue.
>> > GCC also does fairly well on the checksum benchmark with 20051205,
>> > though it does horribly on the checksum benchmark with trunk.
>> > I suspect that the later behavior is due to the fact that on x86_64,
>> > sequences (arrays/vectors) are indexed by 64-bit integers in the
>> > primitive operations (sub, update, etc), but indexed by 32-bit integers
>> > in the user code (Array.sub, Array.update, etc. since Int.int
>> > corresponds to Int32.int ).  Hence, there are quite a few 64/32
>> > conversions going on.
>> >
>> > * I note that with both native codegens and C codegens, with both
>> > 20051205 and trunk, that -align 8 often has a positive impact on
>> > runtime, and rarely has a significant negative impact.  This might be
>> > due to the Opteron memory system.  Aligned reads probably help most on
>> > Real64 intensive benchmarks.
>> >
>> > * The amd64 codegen is doing alright as compared to the x86 codegen.  I
>> > see at most a factor of 2 slowdown, and a few speedups.  Again, I'm not
>> > sure what real conclusions can be drawn.  Some slowdowns are going 
>> to be
>> > due to the changes to the runtime and Basis Library since 20051205; to
>> > isolate those, I need a comparison of 20051205 to trunk on a 32-bit
>> > system.  Some slowdowns are probably going to be due to the sequence
>> > indexing discussed above.
>> >
>> >
>> >
>> > _______________________________________________
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>> > MLton at mlton.org
>> > http://mlton.org/mailman/listinfo/mlton
>> >
>> >
>>
> 
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