Re: [Discuss-gnuradio] Alignment bug fix

[West, Nathan]

On Fri, May 27, 2016 at 12:59 PM, Philip Balister <address@hidden> wrote:

On 05/27/2016 09:43 AM, Robert McGwier wrote:
> Recently a kernel alignment bug was fixed (ugly) and this repaired the
> polyphase synthesis engine in the main code.

A fix in the Linux kernel? Or somewhere else. A reference to the commit
would be handy for people running across this issue.

Philip


>
> My PhD student, Bill Clark (Amateur Radio call KK4EWQ) at Virginia Tech,
> has suffered with and pointed out this problem with the synthesizer for
> some time.
>
> He wrote an out of tree module to correct the difficulty he was
> experiencing but we now believe this work is no longer needed.
>
> Thanks for fixing the bug and thanks to Bill for his hard work at VT.
>
> Bob McGwier
> Professor Electrical and Computer Engineering, VT
> N4HY
>
>

It sounds like Bob might be referring to this commit: https://github.com/gnuradio/gnuradio/commit/6baa4c86c5e1f5889e44a4e8e38750b0de3bf061. It existed for a longer time than necessary because it only impacts people with AVX using binary builds of libfftw that aren't built with AVX. Someone with the issue pointed it out and a small group of us pretty quickly recognized what was happening. From proper bug report to a merged fix was pretty quick.

-Nathan