Re: [PATCH RFC V2 03/10] petf tools: using comm_str to replace comm in hist_entry

From: Jiri Olsa
Date: Mon Sep 18 2017 - 04:38:32 EST


On Wed, Sep 13, 2017 at 12:21:56PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Sun, Sep 10, 2017 at 07:23:16PM -0700, kan.liang@xxxxxxxxx escreveu:
> > From: Kan Liang <kan.liang@xxxxxxxxx>
> >
> > For hist_entry, it only needs comm_str for cmp.
>
> And thinking a bit more, isn't this even a bug fix, as at the time of
> that sample that was the comm string associated with that thread?
>
> Frédéric, am I nutz?

I think it's ok, because struct comm holds just one comm string
which is 'correct/accurate' at the time the hist entry is created

this patch just seems to switch comm pointer with comm string pointer,
I'm guessing it's useful in follow up patches

jirka

>
> - Arnaldo
>
> > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
> > ---
> > tools/perf/util/hist.c | 4 ++--
> > tools/perf/util/sort.c | 8 ++++----
> > tools/perf/util/sort.h | 2 +-
> > 3 files changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> > index e60d8d8..0f00dd9 100644
> > --- a/tools/perf/util/hist.c
> > +++ b/tools/perf/util/hist.c
> > @@ -587,7 +587,7 @@ __hists__add_entry(struct hists *hists,
> > struct namespaces *ns = thread__namespaces(al->thread);
> > struct hist_entry entry = {
> > .thread = al->thread,
> > - .comm = thread__comm(al->thread),
> > + .comm_str = thread__comm_str(al->thread),
> > .cgroup_id = {
> > .dev = ns ? ns->link_info[CGROUP_NS_INDEX].dev : 0,
> > .ino = ns ? ns->link_info[CGROUP_NS_INDEX].ino : 0,
> > @@ -944,7 +944,7 @@ iter_add_next_cumulative_entry(struct hist_entry_iter *iter,
> > .hists = evsel__hists(evsel),
> > .cpu = al->cpu,
> > .thread = al->thread,
> > - .comm = thread__comm(al->thread),
> > + .comm_str = thread__comm_str(al->thread),
> > .ip = al->addr,
> > .ms = {
> > .map = al->map,
> > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> > index eb3ab90..99ab411 100644
> > --- a/tools/perf/util/sort.c
> > +++ b/tools/perf/util/sort.c
> > @@ -114,26 +114,26 @@ static int64_t
> > sort__comm_cmp(struct hist_entry *left, struct hist_entry *right)
> > {
> > /* Compare the addr that should be unique among comm */
> > - return strcmp(comm__str(right->comm), comm__str(left->comm));
> > + return strcmp(right->comm_str, left->comm_str);
> > }
> >
> > static int64_t
> > sort__comm_collapse(struct hist_entry *left, struct hist_entry *right)
> > {
> > /* Compare the addr that should be unique among comm */
> > - return strcmp(comm__str(right->comm), comm__str(left->comm));
> > + return strcmp(right->comm_str, left->comm_str);
> > }
> >
> > static int64_t
> > sort__comm_sort(struct hist_entry *left, struct hist_entry *right)
> > {
> > - return strcmp(comm__str(right->comm), comm__str(left->comm));
> > + return strcmp(right->comm_str, left->comm_str);
> > }
> >
> > static int hist_entry__comm_snprintf(struct hist_entry *he, char *bf,
> > size_t size, unsigned int width)
> > {
> > - return repsep_snprintf(bf, size, "%-*.*s", width, width, comm__str(he->comm));
> > + return repsep_snprintf(bf, size, "%-*.*s", width, width, he->comm_str);
> > }
> >
> > struct sort_entry sort_comm = {
> > diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
> > index f36dc49..861cbe7 100644
> > --- a/tools/perf/util/sort.h
> > +++ b/tools/perf/util/sort.h
> > @@ -96,7 +96,7 @@ struct hist_entry {
> > struct he_stat *stat_acc;
> > struct map_symbol ms;
> > struct thread *thread;
> > - struct comm *comm;
> > + const char *comm_str;
> > struct namespace_id cgroup_id;
> > u64 ip;
> > u64 transaction;
> > --
> > 2.5.5