[x265] [PATCH] fix invalid Instruction Set provided in CLI if CPU doesn't support it

[Dnyaneshwar Gorade]

Ok. I will check if we can use AND mask and provide more information to
user.

On Tue, Nov 3, 2015 at 10:36 AM, Deepthi Nandakumar <
deepthi at multicorewareinc.com> wrote:

> Since the idea here is to correctly log a user-generated error (user-cpuid
> > detected cpuid), the patch is headed in the right direction.
>
> Min's suggestion on using an AND mask sounds good, and can you also make
> the warning more informative (print user-cpuid, and the cpuid we're
> defaulting to) ?
>
> On Thu, Oct 29, 2015 at 11:16 PM, Steve Borho <steve at borho.org> wrote:
>
>> On 10/28, dnyaneshwar at multicorewareinc.com wrote:
>> > # HG changeset patch
>> > # User Dnyaneshwar G <dnyaneshwar at multicorewareinc.com>
>> > # Date 1446021877 -19800
>> > #      Wed Oct 28 14:14:37 2015 +0530
>> > # Node ID 975087370d14e90cd63edecb34fb4bf2feda2468
>> > # Parent  6563218ce342c30bfd4f9bc172a1dab510e6e55b
>> > fix invalid Instruction Set provided in CLI if CPU doesn't support it
>> >
>> > This patch avoids crash/invalid instructions when we provide
>> instruction sets to
>> > be used are higher than the cpu capabilities.
>> >
>> > For example, if our cpu supports instruction sets upto AVX and we
>> provide
>> > --asm "avx2" (AVX2 is higher than AVX) then it will show warning and
>> use default
>> > x265 detected intruction sets.
>>
>> The whole point of having this override is in case our CPU detection is
>> somehow wrong. The user needs to be able to override the detection mask.
>>
>> That said.. if the user provided mask has bits set that were not
>> detected, it's ok to log a serious warning that says you think the
>> encoder is about to break and it is the user's fault.
>>
>> BTW: this feature is often used for benchmarking, to disable certain
>> optimizations piecemeal, but that is not the primary reason why it
>> exists.
>>
>> > diff -r 6563218ce342 -r 975087370d14 source/common/primitives.cpp
>> > --- a/source/common/primitives.cpp    Mon Oct 26 12:13:53 2015 +0530
>> > +++ b/source/common/primitives.cpp    Wed Oct 28 14:14:37 2015 +0530
>> > @@ -238,6 +238,15 @@
>> >              primitives.cu[i].intra_pred_allangs = NULL;
>> >
>> >  #if ENABLE_ASSEMBLY
>> > +
>> > +        if ((uint32_t)param->cpuid > X265_NS::cpu_detect())
>> > +        {
>> > +            if (param->logLevel >= X265_LOG_INFO)
>> > +                x265_log(param, X265_LOG_WARNING, "Unsupported CPUID
>> provided in CLI, so choosing x265 detected CPUID!\n");
>> > +
>> > +            param->cpuid = X265_NS::cpu_detect();
>> > +        }
>> > +
>> >          setupInstrinsicPrimitives(primitives, param->cpuid);
>> >          setupAssemblyPrimitives(primitives, param->cpuid);
>> >  #endif
>> > _______________________________________________
>> > x265-devel mailing list
>> > x265-devel at videolan.org
>> > https://mailman.videolan.org/listinfo/x265-devel
>>
>> --
>> Steve Borho
>> _______________________________________________
>> x265-devel mailing list
>> x265-devel at videolan.org
>> https://mailman.videolan.org/listinfo/x265-devel
>>
>
>
>
> --
> Deepthi Nandakumar
> Engineering Manager, x265
> Multicoreware, Inc
>
> _______________________________________________
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> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
>
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