Re: [PATCH v2 0/2] Basic support for the Ventana VT1 w/ instruction fusion

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/14/22 13:00, Palmer Dabbelt wrote:
> On Sun, 13 Nov 2022 12:48:22 PST (-0800), philipp.tomsich@vrull.eu wrote:
>>
>> This series provides support for the Ventana VT1 (a 4-way superscalar
>> rv64gc_zba_zbb_zbc_zbs_zifenci_xventanacondops core) including support
>> for the supported instruction fusion patterns.
>>
>> This includes the addition of the fusion-aware scheduling
>> infrastructure for RISC-V and implements idiom recognition for the
>> fusion patterns supported by VT1.
>>
>> Note that we don't signal support for XVentanaCondOps at this point,
>> as the XVentanaCondOps support is in-flight separately. Changing the
>> defaults for VT1 can happen late in the cycle, so no need to link the
>> two different changesets.
>>
>> Changes in v2:
>> - Rebased and changed over to .rst-based documentation
>> - Updated to catch more fusion cases
>> - Signals support for Zifencei
>>
>> Philipp Tomsich (2):
>>   RISC-V: Add basic support for the Ventana-VT1 core
>>   RISC-V: Add instruction fusion (for ventana-vt1)
>>
>>  gcc/config/riscv/riscv-cores.def              |   3 +
>>  gcc/config/riscv/riscv-opts.h                 |   2 +-
>>  gcc/config/riscv/riscv.cc                     | 233 ++++++++++++++++++
>>  .../risc-v-options.rst                        |   5 +-
>>  4 files changed, 240 insertions(+), 3 deletions(-)
>
> I guess we never really properly talked about this on the GCC mailing 
> lists, but IMO it's fine to start taking code for designs that have 
> been announced under the assumption that if the hardware doesn't 
> actually show up according to those timelines that it will be assumed 
> to have never existed and thus be removed more quickly than usual.
Absolutely.   I have zero interest in carrying around code for 
nonexistent or dead variants.
>
> That said, I can't find anything describing that the VT-1 exists aside 
> from these patches.  Is there anything that describes this design and 
> when it's expected to be available?

What do you need?  I can give some broad overview information on the 
design, but it would likely just mirror what's already been mentioned in 
these patches.


As far as schedules.  I'm not sure what I can say.  I'll check on that.


It was never my intention to bypass any process/procedures here. So if I 
did, my apologies.


jeff