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

[John Garry]

On 11/06/2019 17:10, Jiri Olsa wrote:
> On Mon, Jun 10, 2019 at 05:59:29PM +0800, John Garry wrote:
> > 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 ','.
> >
> > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> > ---
> >  tools/perf/util/pmu.c | 45 ++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 40 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 036047f56efa..f00cae750086 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -700,6 +700,44 @@ 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)
> > +{
> > +	/*
> > +	 * uncore alias may be from different PMU
> > +	 * with common prefix
> > +	 */
> > +	if (!strncmp(pmu_name, name, strlen(pmu_name)))
> > +		return true;
> > +
> > +	/* match strings with delimiter, ',' */
> > +	while (1) {
> > +		const char *delimiter;
> > +		char token[256] = {};
> > +		const char *found_token;
> > +		int token_len;
> > +
> > +		delimiter = strchr(pmu_name, ',');
> > +		if (delimiter) {
> > +			token_len = delimiter - pmu_name;
> > +		} else {
> > +			token_len = strlen(pmu_name);
> > +		}
> > +
> > +		memcpy(token, pmu_name, token_len);
> > +
> > +		found_token = strstr(name, token);
> > +		if (!found_token)
> > +			return false;
> > +
> > +		/* No more delimiters, so we must be a match */
> > +		if (!delimiter)
> > +			return true;
> > +
> > +		pmu_name += token_len + 1;
> > +		name = found_token + token_len;
> > +	}
>
> hum, would this be easier with strtok_r?

Yes, I think so.

Cheers,

> jirka
>
> .