Messages in this thread | | | Date | Tue, 21 Apr 2015 09:07:33 -0400 | From | Steven Rostedt <> | Subject | Re: perf/tracepoints access to interpreted strings |
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On Mon, 20 Apr 2015 15:26:56 -0600 David Ahern <dsahern@gmail.com> wrote:
> On 4/20/15 3:25 PM, Arnaldo Carvalho de Melo wrote: > > Em Mon, Apr 20, 2015 at 04:46:16PM -0400, Steven Rostedt escreveu: > >> On Wed, 15 Apr 2015 15:09:27 -0300 > >> Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > >>> If it is strictly an enum, i.e. no holes and just by looking at the > >>> "format" file above I don't see how it could have holes, albeit enums > >>> may have, we can as well have this: > > > >>> const char *perf_evsel__enum(struct perf_evsel *evsel, > >>> struct perf_sample *sample, > >>> const char *enum_name); > > > >>> That would return an array of strings that you could directly access, > >>> indexing using some of the fields. > > > >>> I.e. internally we would see the tracepoint format file as: > > > >>> field:enum action vec; offset:12; size:4; signed:0; > > > >>> enum: action: TIMER, NET_TX, NET_RX, BLOCK, BLOCK_IOPOLL, TASKLET, SCHED, HRTIMER, RCU > > > >> Note, with the new TRACE_DEFINE_ENUM() that was already added to > >> Linus's tree, that print_fmt now looks like: > > > >> print fmt: "vec=%u [action=%s]", REC->vec, __print_symbolic(REC->vec, > >> { 0, "HI" }, { 1, "TIMER" }, { 2, "NET_TX" }, { 3, "NET_RX" }, { 4, "BLOCK" }, > >> { 5, "BLOCK_IOPOLL" }, { 6, "TASKLET" }, { 7, "SCHED" }, { 8, "HRTIMER" }, > >> { 9, "RCU" }) > > > > That is better, indeed, covers holes :-) > > Seems to me that means 2 different implementations are needed ... old > and new.
Why? The above is the way most trace points use __print_symbolic(). It's just when a tracepoint uses enums instead of defines or hard coded numbers do the useless enum name pops up.
Any parse should be expecting numbers, not enum names.
-- Steve
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