Update mpg123 during 2021Q1 freeze?

["Dr. Thomas Orgis" <thomas.orgis%uni-hamburg.de@localhost>]

Hi,

as a first measure, it has been suggested to me to update mpg123 in
pkgsrc to fix a nasty performance issue encountered on SPARC with the
pkgsrc build of mpg123 1.26.x.

In short: This line in audio/mpg123/Makefile.common

CONFIGURE_ARGS+=        --with-optimization=0   # our CFLAGS are good enough

causes the default of -ffast-math being dropped from the mpg123 build.
This causes floating point denormals to enter the picture when you use
the proper resampler introduced in 1.26.0. These degrade performance
horribly on SPARC (observed a factor of more than 1000, I kid you not).

This is fixed by letting mpg123 have its default flags, which is

    CFLAGS="-O2 -fomit-frame-pointer -funroll-all-loops -finline-functions -ffast-math $CFLAGS"
.
The environment-provided CFLAGS are appended, and this line is only the
default when GCC is detected.

These flags are unlikely to appear as default pkgsrc CFLAGS, as they
are rather aggressive for general use. But they are what is regularily
used during mpg123 development and arguably for most builds out there.

At the same time, mpg123 1.26.5 avoids the big impact of the missing
flags by adding (literally) a workaround to the filters to avoid
denormals. So a simple update to this bugfix release would also help
independently of the CFLAGS question.

The only other changes in the library fixes parsing of some ID3v2 tags
that would have been mistreated before.

So, is it OK, to

a) drop the CFLAGS line from Makefile.common
b) update audio/mpg123 from 1.26.4 to 1.26.5

during the freeze? At least one of those really should be done,
preferrably both. But I might be biased as mpg123 upstream;-)


Alrighty then,

Thomas

-- 
Dr. Thomas Orgis
HPC @ Universität Hamburg