[webkit-dev] Bring back ARMv6 support to JSC

[Guillaume Emont]

Quoting Filip Pizlo (2017-09-05 10:37:16)
> There isn’t anyone maintaining the 32-not JIT ports to the level of quality we have in our 64-not ports. Making 32-bit use the 64-bit cloop would be a quality progression for actual users of 32-bit. 
> 

Hi,

I would like to chip in as one of the few people that tries to keep the
JIT afloat on mips32, and also advising Caio for the armv6 port. I agree
that support for this is a bit under-resourced (and we at Igalia are
trying to see if we can do something about it), which means that the
mips port tends to lag behind, and only works decently at some points in
time. These points in time mean that WebKit can be relevant on this
platform though. WPE works pretty well on mips, and there is a strong
interest to use it on mips and armv7 set-top-box environments.

If we drop the JIT support, I am afraid that we will lose the
performances that allow WebKit to be relevant for these applications.  I
am working on doing some measurements in real-world applications to
understand how they will be affected exactly and I will report back.

Cheers,

Guillaume


> -Filip
> 
> > On Sep 5, 2017, at 8:02 AM, Adrian Perez de Castro <aperez at igalia.com> wrote:
> > 
> >> On Tue, 5 Sep 2017 16:38:09 +0200, Osztrogonác Csaba <oszi at inf.u-szeged.hu> wrote:
> >> 
> >> [...]
> >> 
> >> Maybe it will be hard to say good bye to 32-bit architecutres
> >> for many people, but please, it's 2017 now, the first ARMv8 SoC
> >> is out 4 years ago, the first AMD64 CPU is out 14 years ago.
> > 
> > While it's true that amd64/x86_64 has been around long enough to not have to
> > care (much) about its 32-bit counterpart; the same cannot be said about ARM.
> > It would be great to be able to say that 32-bit ARM is well dead, but we are
> > not there yet.
> > 
> > If we take x86_64 as an example, it has been “only” 10 years since the last
> > new 32-bit CPU was announced and until 3-4 years ago it wasn't uncommon to
> > see plently of people running 32-bit userlands. If things unroll in a similar
> > way in the ARM arena, I would expect good 32-bit ARM support being relevant
> > at least for another 3-4 years before the need starts to fade away.
> > 
> > If something, I think it may make more sense to remove 32-bit x86 support,
> > and have the 32-bit ARM support around for some more time.
> > 
> > Cheers,
> > 
> > 
> > --
> > Adrián 🎩
> > 
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