[flac-dev] slow on apple silicon?

[Scott Brown]

Martijn filled me in that recent changes (since the official 1.3.4 source)
have added ARM improvements, and that if I get the most recent code, I
should be good.

(I can't get the most recent code to compile, but that's a different story
I suppose)

Thanks,
Scott

On Tue, Jul 5, 2022 at 2:44 PM brianw <brianw at audiobanshee.com> wrote:

> You raise excellent questions. I have not been paying attention to Apple's
> compiler support for the M1, M1 Pro, and M1 Max.
>
> Do you have the latest compiler from Apple?
>
> Are you sure that -O3 is the best option? I seem to recall that the 'best'
> has changed over the years.
>
> I also recall that Apple support for SSE was slow to be delivered, at a
> time when AltiVec support was highly performant. Could it be possible that
> Apple's compiler doesn't support the M1 Max vector instructions as well as
> it support SSE? My experience may not be related to the compiler, though,
> because I was using the vecLib framework, part of the Accelerate framework.
> Initially, Apple provided routines for Intel that were functionally
> correct, but not optimized. Later, those routines were optimized, and
> programs linked against the framework automatically inherited the
> improvements. flac does not use these frameworks, so my example may not be
> relevant.
>
> For comparison, how long does your test set take when going through
> emulation?
>
> Brian
>
>
> On Jul 5, 2022, at 9:48 AM, Scott Brown wrote:
> >
> > Hi everyone,
> >
> > I've got a question regarding Apple Silicon chips and flac encoding. I'm
> not seeing the speed I think I should be seeing
> >
> > I compiled a universal flac 1.3.4 for Apple Silicon and 64 bit intel
> like so:
> >
> > ./configure -enable-static -disable-shared CFLAGS=" -arch arm64 -arch
> x86_64 -isysroot
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
> -mmacosx-version-min=10.9 -O3" ; make
> >
> > Encoding 24/96 wav files to flac level 8 for a fileset i've been testing
> takes about 3 minutes and 10 seconds on an M1 Max processor using the
> native arm build.
> >
> > Using the intel build on the M1 Max (which goes through Apple's Rosetta
> emulation) takes 1 minute and 50 seconds.
> >
> > I would expect the native Arm build to be much faster since it's not
> going through emulation. What am I missing? Some compilation flag?
> >
> > Thanks,
> > Scott
>
>
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