linux-kernel - Re: [PATCH 07/24] selftests/resctrl: Split measure_cache

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Message-ID: <12945b6d-0cc5-4dda-97b3-ec2b597f6ad5@intel.com>
Date:   Thu, 2 Nov 2023 10:48:22 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        <linux-kselftest@...r.kernel.org>, Shuah Khan <shuah@...nel.org>,
        "Shaopeng Tan" <tan.shaopeng@...fujitsu.com>,
        Maciej Wieczór-Retman 
        <maciej.wieczor-retman@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>
CC:     <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 07/24] selftests/resctrl: Split measure_cache_vals()
 function

Hi Ilpo,

On 10/24/2023 2:26 AM, Ilpo Järvinen wrote:
> The measure_cache_vals() function does a different thing depending on

No need to say "function" when using "()". The above can just be:
"measure_cache_vals() does a different ..."

> the test case that called it:
>   - For CAT, it measures LLC perf misses.
>   - For CMT, it measures LLC occupancy through resctrl.
> 
> Split these two functionalities into own functions the CAT and CMT
> tests can call directly.
> 
> Co-developed-by: Fenghua Yu <fenghua.yu@...el.com>
> Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> ---
>  tools/testing/selftests/resctrl/cache.c       | 37 ++++++++++---------
>  tools/testing/selftests/resctrl/resctrl.h     |  2 +-
>  tools/testing/selftests/resctrl/resctrl_val.c |  2 +-
>  3 files changed, 21 insertions(+), 20 deletions(-)
> 
> diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/selftests/resctrl/cache.c
> index bcbca356d56a..299d9508221f 100644
> --- a/tools/testing/selftests/resctrl/cache.c
> +++ b/tools/testing/selftests/resctrl/cache.c
> @@ -170,35 +170,36 @@ static int print_results_cache(char *filename, int bm_pid,
>  	return 0;
>  }
>  
> -int measure_cache_vals(struct resctrl_val_param *param, int bm_pid)
> +static int measure_llc_perf(struct resctrl_val_param *param, int bm_pid)
>  {
> -	unsigned long llc_perf_miss = 0, llc_occu_resc = 0, llc_value = 0;
> +	unsigned long llc_perf_miss = 0;
>  	int ret;
>  
>  	/*
>  	 * Measure cache miss from perf.
>  	 */

I'd expect these comments to move as part of a change like this,
but seems like this is merged with other changes in patch 10. Does not
seem like an issue done in this way.

> -	if (!strncmp(param->resctrl_val, CAT_STR, sizeof(CAT_STR))) {
> -		ret = get_llc_perf(&llc_perf_miss);
> -		if (ret < 0)
> -			return ret;
> -		llc_value = llc_perf_miss;
> -	}
> +	ret = get_llc_perf(&llc_perf_miss);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = print_results_cache(param->filename, bm_pid, llc_perf_miss);
> +	return ret;
> +}
> +
> +int measure_llc_resctrl(struct resctrl_val_param *param, int bm_pid)
> +{
> +	unsigned long llc_occu_resc = 0;
> +	int ret;
>  
>  	/*
>  	 * Measure llc occupancy from resctrl.
>  	 */
> -	if (!strncmp(param->resctrl_val, CMT_STR, sizeof(CMT_STR))) {
> -		ret = get_llc_occu_resctrl(&llc_occu_resc);
> -		if (ret < 0)
> -			return ret;
> -		llc_value = llc_occu_resc;
> -	}
> -	ret = print_results_cache(param->filename, bm_pid, llc_value);
> -	if (ret)
> +	ret = get_llc_occu_resctrl(&llc_occu_resc);
> +	if (ret < 0)
>  		return ret;
>  
> -	return 0;
> +	ret = print_results_cache(param->filename, bm_pid, llc_occu_resc);
> +	return ret;
>  }
>  
>  /*
> @@ -253,7 +254,7 @@ int cat_val(struct resctrl_val_param *param, size_t span)
>  		}
>  
>  		sleep(1);
> -		ret = measure_cache_vals(param, bm_pid);
> +		ret = measure_llc_perf(param, bm_pid);
>  		if (ret)
>  			goto pe_close;
>  	}


Reinette