Re: [patch V2 01/17] x86/vdso: Mark the TSC clocksource path likely

[Vincenzo Frascino]

On 2/7/20 12:38 PM, Thomas Gleixner wrote:
> Jumping out of line for the TSC clcoksource read is creating awful
> code. TSC is likely to be the clocksource at least on bare metal and the PV
> interfaces are sufficiently more work that the jump over the TSC read is
> just in the noise.
>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>

> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  arch/x86/include/asm/vdso/gettimeofday.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/arch/x86/include/asm/vdso/gettimeofday.h
> +++ b/arch/x86/include/asm/vdso/gettimeofday.h
> @@ -243,7 +243,7 @@ static u64 vread_hvclock(void)
>  
>  static inline u64 __arch_get_hw_counter(s32 clock_mode)
>  {
> -	if (clock_mode == VCLOCK_TSC)
> +	if (likely(clock_mode == VCLOCK_TSC))
>  		return (u64)rdtsc_ordered();
>  	/*
>  	 * For any memory-mapped vclock type, we need to make sure that gcc
> 

-- 
Regards,
Vincenzo