Re: [PATCH] x86/cpu: Use prefetcht0 for prefetch() on 64-bit

[Andi Kleen]

> +#ifdef CONFIG_X86_64
> +/*
> + * Every x86-64 CPU has prefetcht0. Not __builtin_prefetch(): the kernel
> + * builds with -mno-sse, and clang then drops the builtin without a warning.
> + */
> +static inline void prefetch(const void *x)
> +{
> +	asm("prefetcht0 %0" : : "m" (*(const char *)x));
> +}
> +#else

One thing you should check if the inline assembly pessimizes the code on
gcc. Normally builtins can be better optimized. Or keep using the builtin
on gcc to be safe.

-Andi