[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] tcg/ppc: Add vector opcodes
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH] tcg/ppc: Add vector opcodes |
Date: |
Fri, 22 Feb 2019 12:20:06 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 2/22/19 9:13 AM, Mark Cave-Ayland wrote:
> On 22/02/2019 05:59, Richard Henderson wrote:
>
>> This requires VSX, not just Altivec, so Power7 or later.
>>
>> Signed-off-by: Richard Henderson <address@hidden>
>> ---
>>
>> At present there are no tunables that can avoid the 64-bit element
>> load/store requirement. As with requiring AVX1 for x86 hosts, I'm
>> not sure it's worth inventing such a tunable for pre-power7 hosts.
>>
>> Tested vs aarch64 risu test cases. It's probably worth testing
>> this vs Mark's target/ppc conversion.
>
> Oooh this looks really exciting! However... I only have a G4 Mac Mini around
> that I
> use for testing which is Altivec-only :( Is it much work to support non-VSX
> hosts?
Hmm, dunno. I'll think about it.
> This leads me to a related point that came up when Howard and I were testing
> the PPC
> vector patches - how do we know at runtime which optimisations were being
> used, e.g.
> what is the value of have_avx2 on a particular CPU running QEMU?
There is no way from within qemu itself.
> Under Linux this isn't too bad since you can just do "cat /proc/cpuinfo |
> grep avx2"
> but it becomes more tricky when getting bug reports from Windows users who
> aren't
> particularly technical...
Something like:
https://www.intel.com/content/www/us/en/support/articles/000005651/processors.html
or any one of several other utilities that can display cpuid information.
r~
Re: [Qemu-devel] [PATCH] tcg/ppc: Add vector opcodes, no-reply, 2019/02/27