Em Fri, Jun 26, 2020 at 02:44:14PM -0700, Ian Rogers escreveu: > On Fri, Jun 26, 2020 at 2:25 PM Andi Kleen <[email protected]> wrote: > > On Fri, Jun 26, 2020 at 09:47:10PM +0200, Jiri Olsa wrote: > > > this patchset is adding the support to reused metric in another > > > metric. The metric needs to be referenced by 'metric:' prefix.
> > Why is the prefix needed? > > Could just look it up without prefix. > The name could be a metric or an event, the logic for each is quite > different. You could look up an event and when it fails assume it was > a metric, but I like the simplicity of this approach. Maybe this > change could be adopted more widely with something like "perf stat -e > metric:IPC -a -I 1000" rather than the current "perf stat -M IPC -a -I > 1000". Humm, the more concise, the better, so I think that we should use metric: when we notice ambiguity, i.e. we should first lookup the provided name as an event, and even if it resolves, look it up as well as a metric, if both lookups work, then one need to disambiguate. But then, why should we pick a name for a metric that is also a name for an event? Can you think about a concrete case? Can't we detect this at build time, when introducing the new metric and bail out? - Arnaldo
