Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs

[Robert Richter <robert.richter@amd.com>]

On 26.08.10 17:14:24, Don Zickus wrote:
> diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
> index 4539b4b..d16ebd8 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel.c
> @@ -738,6 +738,7 @@ again:
>  
>  	inc_irq_stat(apic_perf_irqs);
>  	ack = status;
> +	intel_pmu_ack_status(ack);

I would slightly change the patch:

There is no need for the ack variable anymore, you could directly work
with the status.

I would call intel_pmu_ack_status() as close as possible after the
intel_pmu_get_status(), which is after 'again:'.

-Robert

>  
>  	intel_pmu_lbr_read();
>  
> @@ -766,8 +767,6 @@ again:
>  			x86_pmu_stop(event);
>  	}
>  
> -	intel_pmu_ack_status(ack);
> -
>  	/*
>  	 * Repeat if there is more work to be done:
>  	 */
> 

-- 
Advanced Micro Devices, Inc.
Operating System Research Center