Re: [PATCH v2 2/5] perf pmu: Support more complex PMU event aliasing

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: John Garry <john.garry@huawei.com>
Cc: mark.rutland@arm.com, brueckner@linux.ibm.com,
	mathieu.poirier@linaro.org, peterz@infradead.org,
	ben@decadent.org.uk, tmricht@linux.ibm.com, will.deacon@arm.com,
	linux-kernel@vger.kernel.org, linuxarm@huawei.com,
	zhangshaokun@hisilicon.com, alexander.shishkin@linux.intel.com,
	mingo@redhat.com, namhyung@kernel.org, jolsa@redhat.com,
	linux-arm-kernel@lists.infradead.org, kan.liang@linux.intel.com
Subject: Re: [PATCH v2 2/5] perf pmu: Support more complex PMU event aliasing
Date: Fri, 14 Jun 2019 11:50:57 -0300	[thread overview]
Message-ID: <20190614145057.GG1402@kernel.org> (raw)
In-Reply-To: <1560521283-73314-3-git-send-email-john.garry@huawei.com>

Em Fri, Jun 14, 2019 at 10:08:00PM +0800, John Garry escreveu:
> The jevent "Unit" field is used for uncore PMU alias definition.
> 
> The form uncore_pmu_example_X is supported, where "X" is a wildcard,
> to support multiple instances of the same PMU in a system.
> 
> Unfortunately this format not suitable for all uncore PMUs; take the Hisi
> DDRC uncore PMU for example, where the name is in the form
> hisi_scclX_ddrcY.
> 
> For the current jevent parsing, we would be required to hardcode an uncore
> alias translation for each possible value of X. This is not scalable.
> 
> Instead, add support for "Unit" field in the form "hisi_sccl,ddrc", where
> we can match by hisi_scclX and ddrcY. Tokens in Unit field are 
> delimited by ','.

Looks ok, but would be good to have some Reviewed-by attached as I'm not
super familiar with the PMU oddities, Jiri, can you please review this,
somebody else?

Thanks,

- Arnaldo

> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
>  tools/perf/util/pmu.c | 39 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 34 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 7e7299fee550..bc71c60589b5 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -700,6 +700,39 @@ struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu)
>  	return map;
>  }
>  
> +static bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
> +{
> +	char *tmp, *tok, *str;
> +	bool res;
> +
> +	str = strdup(pmu_name);
> +	if (!str)
> +		return false;
> +
> +	/*
> +	 * uncore alias may be from different PMU with common
> +	 * prefix or matching tokens.
> +	 */
> +	tok = strtok_r(str, ",", &tmp);
> +	if (strncmp(pmu_name, tok, strlen(tok))) {
> +		res = false;
> +		goto out;
> +	}
> +
> +	for (; tok; name += strlen(tok), tok = strtok_r(NULL, ",", &tmp)) {
> +		name = strstr(name, tok);
> +		if (!name) {
> +			res = false;
> +			goto out;
> +		}
> +	}
> +
> +	res = true;
> +out:
> +	free(str);
> +	return res;
> +}
> +
>  /*
>   * From the pmu_events_map, find the table of PMU events that corresponds
>   * to the current running CPU. Then, add all PMU events from that table
> @@ -730,12 +763,8 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
>  			break;
>  		}
>  
> -		/*
> -		 * uncore alias may be from different PMU
> -		 * with common prefix
> -		 */
>  		if (pmu_is_uncore(name) &&
> -		    !strncmp(pname, name, strlen(pname)))
> +		    pmu_uncore_alias_match(pname, name))
>  			goto new_alias;
>  
>  		if (strcmp(pname, name))
> -- 
> 2.17.1

-- 

- Arnaldo

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel