Re: armhf NEON exception for chromium

[Timothy Pearson <tpearson@raptorengineering.com>]

----- Original Message -----
> From: "Paul Tagliamonte" <paultag@debian.org>
> To: "Andres Salomon" <dilinger@queued.net>
> Cc: debian-devel@lists.debian.org, "Timothy Pearson" <tpearson@raptorengineering.com>, debian-ci@lists.debian.org
> Sent: Friday, September 15, 2023 11:29:56 AM
> Subject: Re: armhf NEON exception for chromium

> On Fri, Sep 15, 2023 at 12:18 PM Andres Salomon <dilinger@queued.net> wrote:
>> So my proposal for chromium is this:
>> a) Enable NEON for chromium's armhf build.
>> b) Add a check in debian/rules for 'neon' in /proc/cpuinfo's Features: line, and
>> fail to build if NEON is not present. This should ensure that any buildds or
>> downstream builders don't waste resources configuring/building chromium on a
>> non-NEON board only to have it fail somewhere in the middle.
>> c) Using the current shell script wrapper for chromium (which already checks for
>> things like SSE3 cpu instructions on x86), check for NEON support at startup by
>> also looking for the string 'neon' in /proc/cpuinfo; if NEON is not supported,
>> print an error message and exit before launching the chromium binary.
>> d) Ask the buildd admins to restrict building of chromium from any Armada XP
>> buildds, which appear to be the only armhf buildds left in rotation that lack
>> NEON support. If they are unwilling/unable to do this, then I'll have to play
>> the giveback game for armhf (step right up! everyone's a winner!), which I
>> often end up having to do currently because the 2-3 day armhf builds will
>> sometimes hang/crash halfway through.
> 
> This seems like a very good idea to me. I doubt anyone running
> chromium on an armhf at this point would try to do so on anything that
> doesn't support NEON. As a user (and developer targeting armhf) this
> seems like a win for users, IMVHO.
> 
>  paultag
> 
> --
> :wq

I am also in agreement here.  Chromium is resource intensive enough that it basically needs vector instructions (notably in skia), if not a full-blown GPU, to be useful.