ghc -fasm declared not too shabby

Donald Bruce Stewart dons at
Thu Mar 1 05:59:26 EST 2007

> Donald Bruce Stewart wrote:
> >Got some initial nobench numbers for ghc head -fvia-C versus -fasm, on
> >amd64:
> >
> >
> >
> >Overall all of nobench, ghc -fasm averages 3% slower. Not too shabby!
> >There's some wider variation on the microbenchmarks in the imaginary
> >class:
> >
> >    one case 20% faster, another 30% slower, average 2% slower.
> nsieve is interesting... I'm looking into it now.  Also the HEAD seems 
> slower on that program.
> >On real programs though, 3% slower on average.
> >The big benefit of course, no perl, no gcc and faster compilation times.
> I'd thought that -fasm was a slight improvement over -fvia-C on x86_64, so 
> this is a surprise to me.  I know it's slower on x86, mainly due to the 
> poor code generationg for floating point on x86.

Initial x86 numbers now up, note the (known) floating point issues: 

> You might consider discounting the programs that run for less than 0.1 
> seconds from the average, that's what nofib-analyse does.

Good idea. Will do. I'll see if I can increase the runtime on a few

> BTW, what happened to imaginary/rfib?  I find that a useful floating point 
> microbenchmark.

Ah right. It was subsumed with the 'recursive' benchmark, but it might
be useful to have back since its smaller. I'll add it.

-- Don

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