Re: [PATCH 2/4] selftests/resctrl: Don't hard code divisor in MBM results

[Reinette Chatre]

Hi Ilpo,

The subject is "Don't hard code divisor ..." yet it seems to me
that the hard coding persists. It is just changed from a magic
constant to a macro.

On 2/8/2023 1:40 AM, Ilpo Järvinen wrote:
> From: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> 
> Presently, while calculating MBM results, the divisor is hard coded as 4.

"Presently" can be removed. Here and in the rest of the series the usage of
"presently" and "currently" can usually be removed to improve clarity.

> It's hard coded to 4 because "NUM_OF_RUNS" is defined as 5 and the test
> does not count first result and hence 4. So, instead of hard coding the
> value to 4, change it to NUM_OF_RUNS - 1.

Are there any plans surrounding using struct resctrl_val_param::num_of_runs
instead?

> 
> Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>

Missing your Signed-off-by?

> ---
>  tools/testing/selftests/resctrl/mbm_test.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
> index 8392e5c55ed0..4f85cbbfd037 100644
> --- a/tools/testing/selftests/resctrl/mbm_test.c
> +++ b/tools/testing/selftests/resctrl/mbm_test.c
> @@ -31,8 +31,8 @@ show_bw_info(unsigned long *bw_imc, unsigned long *bw_resc, int span)
>  		sum_bw_resc += bw_resc[runs];
>  	}
>  
> -	avg_bw_imc = sum_bw_imc / 4;
> -	avg_bw_resc = sum_bw_resc / 4;
> +	avg_bw_imc = sum_bw_imc / (NUM_OF_RUNS - 1);
> +	avg_bw_resc = sum_bw_resc / (NUM_OF_RUNS - 1);
>  	avg_diff = (float)labs(avg_bw_resc - avg_bw_imc) / avg_bw_imc;
>  	avg_diff_per = (int)(avg_diff * 100);
>  


Reinette