Messages in this thread | | | Date | Wed, 7 Jul 2021 20:15:38 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 6/7] libperF: Add group support to perf_evsel__open |
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On Wed, Jul 07, 2021 at 02:43:07PM -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Jul 06, 2021 at 05:17:03PM +0200, Jiri Olsa escreveu: > > Adding support to set group_fd in perf_evsel__open > > call and make it to follow the group setup. > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > --- > > tools/lib/perf/evsel.c | 26 ++++++++++++++++++++++++-- > > 1 file changed, 24 insertions(+), 2 deletions(-) > > > > diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c > > index 3e6638d27c45..9ebf7122d476 100644 > > --- a/tools/lib/perf/evsel.c > > +++ b/tools/lib/perf/evsel.c > > @@ -17,6 +17,7 @@ > > #include <linux/string.h> > > #include <sys/ioctl.h> > > #include <sys/mman.h> > > +#include <asm/bug.h> > > > > void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr, > > int idx) > > @@ -76,6 +77,25 @@ sys_perf_event_open(struct perf_event_attr *attr, > > return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); > > } > > > > +static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread) > > +{ > > + struct perf_evsel *leader = evsel->leader; > > + int fd; > > + > > + if (evsel == leader) > > + return -1; > > + > > + /* > > + * Leader must be already processed/open, > > + * if not it's a bug. > > + */ > > + BUG_ON(!leader->fd); > > Humm, having panics in library code looks ugly, why can't we just return > some errno and let the whatever is using the library to fail gracefully?
true, I took it from perf code, did not realize this, I'll check what can we do in ehre
> > I applied the patches so far, will make them available at tmp.perf/core > now.
great, I'll take the patches from there for my next change
thanks, jirka
> > - Arnaldo > > > + fd = FD(leader, cpu, thread); > > + BUG_ON(fd == -1); > > + return fd; > > +} > > + > > int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus, > > struct perf_thread_map *threads) > > { > > @@ -111,11 +131,13 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus, > > > > for (cpu = 0; cpu < cpus->nr; cpu++) { > > for (thread = 0; thread < threads->nr; thread++) { > > - int fd; > > + int fd, group_fd; > > + > > + group_fd = get_group_fd(evsel, cpu, thread); > > > > fd = sys_perf_event_open(&evsel->attr, > > threads->map[thread].pid, > > - cpus->map[cpu], -1, 0); > > + cpus->map[cpu], group_fd, 0); > > > > if (fd < 0) > > return -errno; > > -- > > 2.31.1 > > > > -- > > - Arnaldo >
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