linux-kernel - Re: [PATCH 2/2] perf tools: Improve IBS error handling

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Message-ID: <YV8uQVnMnnMd1Led@krava>
Date:   Thu, 7 Oct 2021 19:28:33 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Kim Phillips <kim.phillips@....com>
Cc:     Arnaldo Carvalho de Melo <acme@...hat.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Ian Rogers <irogers@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Joao Martins <joao.m.martins@...cle.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Mark Rutland <mark.rutland@....com>,
        Michael Petlan <mpetlan@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Robert Richter <robert.richter@....com>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 2/2] perf tools: Improve IBS error handling

On Mon, Oct 04, 2021 at 04:41:14PM -0500, Kim Phillips wrote:

SNIP

> ---
>  tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index b915840690d4..f8a9cbd99314 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -2743,9 +2743,22 @@ static bool find_process(const char *name)
>  	return ret ? false : true;
>  }
>  
> +static bool is_amd(const char *arch, const char *cpuid)
> +{
> +	return arch && !strcmp("x86", arch) && cpuid && strstarts(cpuid, "AuthenticAMD");
> +}
> +
> +static bool is_amd_ibs(struct evsel *evsel)
> +{
> +	return evsel->core.attr.precise_ip || !strncmp(evsel->pmu_name, "ibs", 3);
> +}
> +
>  int evsel__open_strerror(struct evsel *evsel, struct target *target,
>  			 int err, char *msg, size_t size)
>  {
> +	struct perf_env *env = evsel__env(evsel);
> +	const char *arch = perf_env__arch(env);
> +	const char *cpuid = perf_env__cpuid(env);
>  	char sbuf[STRERR_BUFSIZE];
>  	int printed = 0, enforced = 0;
>  
> @@ -2841,6 +2854,17 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
>  			return scnprintf(msg, size, "wrong clockid (%d).", clockid);
>  		if (perf_missing_features.aux_output)
>  			return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
> +		if (is_amd(arch, cpuid)) {
> +			if (is_amd_ibs(evsel)) {

would single 'is_amd_ibs' call be better? checking on both amd and ibs

jirka

> +				if (evsel->core.attr.exclude_kernel)
> +					return scnprintf(msg, size, 
> +	"AMD IBS can't exclude kernel events.  Try running at a higher privilege level.");
> +				if (!evsel->core.system_wide)
> +					return scnprintf(msg, size,
> +	"AMD IBS may only be available in system-wide/per-cpu mode.  Try using -a, or -C and workload affinity");
> +			}
> +		}
> +
>  		break;
>  	case ENODATA:
>  		return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. "
> -- 
> 2.31.1
>