Re: [PATCH] perf evlist: Fix the warning logic about warn_user_request_cpu

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, Mar 18, 2024 at 08:11:50PM +0800, Chunxin Zang wrote:
> The old logic in evlist__warn_user_requested_cpus incorrectly output
> the warning message when I run 'perf record -C xxx' command on my
> context(the cpu has 8 performance-cores and 8 efficient-cores.).
> 
> The old warning like this:
>   # perf record -C 17
>   WARNING: A requested CPU in '17' is not supported by PMU 'cpu_core' (CPUs 0-15) for event 'cycles:P'
>   # perf record -C 14
>   WARNING: A requested CPU in '14' is not supported by PMU 'cpu_atom' (CPUs 16-23) for event 'cycles:P'
>   # perf record -C 14-17
>   WARNING: A requested CPU in '15-16' is not supported by PMU 'cpu_atom' (CPUs 16-23) for event 'cycles:P'
>   WARNING: A requested CPU in '15-16' is not supported by PMU 'cpu_core' (CPUs 0-15) for event 'cycles:P'
> 
> After patching, the warning is as follows
>   # perf record -C 17
>   WARNING: A requested CPU '17' in '17' is not supported by PMU 'cpu_atom' (CPUs 16-23) for event 'cycles:P'

Looks wrong, i.e. I ask for CPU 17 and it says it is not in the range
16-23?

Ditto for the rest, no?

- Arnaldo

>   # perf record -C 14
>   WARNING: A requested CPU '14' in '14' is not supported by PMU 'cpu_core' (CPUs 0-15) for event 'cycles:P'
>   # perf record -C 15-18
>   WARNING: A requested CPU '16-18' in '15-18' is not supported by PMU 'cpu_atom' (CPUs 16-23) for event 'cycles:P'
>   WARNING: A requested CPU '15' in '15-18' is not supported by PMU 'cpu_core' (CPUs 0-15) for event 'cycles:P'
> 
> Signed-off-by: Chunxin Zang <spring.cxz@gmail.com>
> Reviewed-by: Chen Yang <yangchen11@lixiang.com>
> ---
>  tools/perf/util/evlist.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 55a300a0977b..82fee2e29966 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -2514,12 +2514,16 @@ void evlist__warn_user_requested_cpus(struct evlist *evlist, const char *cpu_lis
>  
>  		to_test = pmu && pmu->is_core ? pmu->cpus : cpu_map__online();
>  		intersect = perf_cpu_map__intersect(to_test, user_requested_cpus);
> -		if (!perf_cpu_map__equal(intersect, user_requested_cpus)) {
> -			char buf[128];
>  
> -			cpu_map__snprint(to_test, buf, sizeof(buf));
> -			pr_warning("WARNING: A requested CPU in '%s' is not supported by PMU '%s' (CPUs %s) for event '%s'\n",
> -				cpu_list, pmu ? pmu->name : "cpu", buf, evsel__name(pos));
> +		if (intersect && perf_cpu_map__is_subset(user_requested_cpus, intersect)) {
> +			char buf_test[128];
> +			char buf_intersect[128];
> +
> +			cpu_map__snprint(to_test, buf_test, sizeof(buf_test));
> +			cpu_map__snprint(intersect, buf_intersect, sizeof(buf_intersect));
> +			pr_warning("WARNING: A requested CPU '%s' in '%s' is not supported by "
> +				   "PMU '%s' (CPUs %s) for event '%s'\n", buf_intersect, cpu_list,
> +				   pmu ? pmu->name : "cpu", buf_test, evsel__name(pos));
>  		}
>  		perf_cpu_map__put(intersect);
>  	}
> -- 
> 2.34.1