Messages in this thread | | | From | Ian Rogers <> | Date | Thu, 22 Jun 2023 17:56:30 -0700 | Subject | Re: [PATCH] tools lib subcmd: Show parent options in help |
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On Thu, Jun 22, 2023 at 3:28 PM Namhyung Kim <namhyung@kernel.org> wrote: > > On Wed, Jun 21, 2023 at 12:05 AM Ian Rogers <irogers@google.com> wrote: > > > > On Thu, May 25, 2023 at 3:09 PM Namhyung Kim <namhyung@kernel.org> wrote: > > > > > > I've just realized that help message in a subcommand didn't show one > > > in the parent command. Since the option parser understands the parent, > > > display code should do the same. For example, `perf ftrace latency -h` > > > should show options in the `perf ftrace` command too. > > > > > > Before: > > > > > > $ perf ftrace latency -h > > > > > > Usage: perf ftrace [<options>] [<command>] > > > or: perf ftrace [<options>] -- [<command>] [<options>] > > > or: perf ftrace {trace|latency} [<options>] [<command>] > > > or: perf ftrace {trace|latency} [<options>] -- [<command>] [<options>] > > > > > > -b, --use-bpf Use BPF to measure function latency > > > -n, --use-nsec Use nano-second histogram > > > -T, --trace-funcs <func> > > > Show latency of given function > > > > > > After: > > > > > > $ perf ftrace latency -h > > > > > > Usage: perf ftrace [<options>] [<command>] > > > or: perf ftrace [<options>] -- [<command>] [<options>] > > > or: perf ftrace {trace|latency} [<options>] [<command>] > > > or: perf ftrace {trace|latency} [<options>] -- [<command>] [<options>] > > > > > > -a, --all-cpus System-wide collection from all CPUs > > > -b, --use-bpf Use BPF to measure function latency > > > -C, --cpu <cpu> List of cpus to monitor > > > -n, --use-nsec Use nano-second histogram > > > -p, --pid <pid> Trace on existing process id > > > -T, --trace-funcs <func> > > > Show latency of given function > > > -v, --verbose Be more verbose > > > --tid <tid> Trace on existing thread id (exclusive to --pid) > > > > > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > > > --- > > > tools/lib/subcmd/parse-options.c | 26 ++++++++++++++++++-------- > > > 1 file changed, 18 insertions(+), 8 deletions(-) > > > > > > diff --git a/tools/lib/subcmd/parse-options.c b/tools/lib/subcmd/parse-options.c > > > index 9fa75943f2ed..41de97671c72 100644 > > > --- a/tools/lib/subcmd/parse-options.c > > > +++ b/tools/lib/subcmd/parse-options.c > > > @@ -806,18 +806,28 @@ static int option__cmp(const void *va, const void *vb) > > > > > > static struct option *options__order(const struct option *opts) > > > { > > > - int nr_opts = 0, nr_group = 0, len; > > > - const struct option *o = opts; > > > - struct option *opt, *ordered, *group; > > > + int nr_opts = 0, nr_group = 0, nr_parent = 0, len; > > > + const struct option *o, *p = opts; > > > + struct option *opt, *ordered = NULL, *group; > > > > > > - for (o = opts; o->type != OPTION_END; o++) > > > +retry: > > > > Why use "goto retry" and not compute the size with the parent upfront? > > No specific reason, just followed the same pattern as in > parse_{short,long}_opt(). :)
:-) Could those loops not be:
for (; options; options = options->parent) { ... }
rather than using a goto?
> > > > > + for (o = p; o->type != OPTION_END; o++) > > > ++nr_opts; > > > > > > - len = sizeof(*o) * (nr_opts + 1); > > > - ordered = malloc(len); > > > - if (!ordered) > > > + len = sizeof(*o) * (nr_opts + !o->parent); > > > > It'd be nice to comment on why the "!o->parent" here. > > What about this? > > /* It needs a terminating NULL entry when there's no parent */
Perhaps: the length is given by the number of options plus a null terminator for the last loop iteration.
It may be cleaner to just compute this after nr_opts settles. perhaps something along the lines of:
for (p = .. ; p; p = p->parent) for (o = p; o->type != OPTION_END; o++) ++nr_opts; len = sizeof(*o) * (nr_opts + 1); /* +1 for terminator */
Thanks, Ian
> Thanks, > Namhyung > > > > > > Thanks, > > Ian > > > > > + group = realloc(ordered, len); > > > + if (!group) > > > goto out; > > > - memcpy(ordered, opts, len); > > > + ordered = group; > > > + memcpy(&ordered[nr_parent], p, sizeof(*o) * (nr_opts - nr_parent)); > > > + > > > + if (o->parent) { > > > + p = o->parent; > > > + nr_parent = nr_opts; > > > + goto retry; > > > + } > > > + /* copy the last OPTION_END */ > > > + memcpy(&ordered[nr_opts], o, sizeof(*o)); > > > > > > /* sort each option group individually */ > > > for (opt = group = ordered; opt->type != OPTION_END; opt++) { > > > -- > > > 2.41.0.rc0.172.g3f132b7071-goog > > >
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