Re: [PATCH 2/2] util: add util function buffer_zero_avx512()

[Robert Hoo]

On Thu, 2020-02-13 at 11:30 +0100, Paolo Bonzini wrote:
> On 13/02/20 08:52, Robert Hoo wrote:
> > +
> > +}
> > +#pragma GCC pop_options
> > +#endif
> > +
> > +
> >  /* Note that for test_buffer_is_zero_next_accel, the most
> > preferred
> >   * ISA must have the least significant bit.
> >   */
> > -#define CACHE_AVX2    1
> > -#define CACHE_SSE4    2
> > -#define CACHE_SSE2    4
> > +#define CACHE_AVX512F 1
> > +#define CACHE_AVX2    2
> > +#define CACHE_SSE4    4
> > +#define CACHE_SSE2    6
> 
> This should be 8, not 6.
> 
> Paolo

Thanks Paolo, going to fix it in v2.
> 
> >  
> >  /* Make sure that these variables are appropriately initialized
> > when
> >   * SSE2 is enabled on the compiler command-line, but the compiler
> > is
> > @@ -226,6 +268,11 @@ static void init_accel(unsigned cache)
> >          fn = buffer_zero_avx2;
> >      }
> >  #endif
> > +#ifdef CONFIG_AVX512F_OPT
> > +    if (cache & CACHE_AVX512F) {
> > +        fn = buffer_zero_avx512;
> > +    }
> > +#endif
> >      buffer_accel = fn;
> >  }
> >  
> > @@ -255,6 +302,9 @@ static void __attribute__((constructor))
> > init_cpuid_cache(void)
> >              if ((bv & 6) == 6 && (b & bit_AVX2)) {
> >                  cache |= CACHE_AVX2;
> >              }
> > +            if ((bv & 6) == 6 && (b & bit_AVX512F)) {
> > +                cache |= CACHE_AVX512F;
> > +            }
> >          }
> 
>