Commit d56354dc authored Mar 11, 2019 by Song Liu Committed by Arnaldo Carvalho de Melo Mar 21, 2019

perf tools: Save bpf_prog_info and BTF of new BPF programs



To fully annotate BPF programs with source code mapping, 4 different
information are needed:

    1) PERF_RECORD_KSYMBOL
    2) PERF_RECORD_BPF_EVENT
    3) bpf_prog_info
    4) btf

This patch handles 3) and 4) for BPF programs loaded after 'perf
record|top'.

For timely process of these information, a dedicated event is added to
the side band evlist.

When PERF_RECORD_BPF_EVENT is received via the side band event, the
polling thread gathers 3) and 4) vis sys_bpf and store them in perf_env.

This information is saved to perf.data at the end of 'perf record'.

Committer testing:

The 'wakeup_watermark' member in 'struct perf_event_attr' is inside a
unnamed union, so can't be used in a struct designated initialization
with older gccs, get it out of that, isolating as 'attr.wakeup_watermark
= 1;' to work with all gcc versions.

We also need to add '--no-bpf-event' to the 'perf record'
perf_event_attr tests in 'perf test', as the way that that test goes is
to intercept the events being setup and looking if they match the fields
described in the control files, since now it finds first the side band
event used to catch the PERF_RECORD_BPF_EVENT, they all fail.

With these issues fixed:

Same scenario as for testing BPF programs loaded before 'perf record' or
'perf top' starts, only start the BPF programs after 'perf record|top',
so that its information get collected by the sideband threads, the rest
works as for the programs loaded before start monitoring.

Add missing 'inline' to the bpf_event__add_sb_event() when
HAVE_LIBBPF_SUPPORT is not defined, fixing the build in systems without
binutils devel files installed.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-16-songliubraving@fb.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 657ee553

tools/perf/builtin-record.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1238,6 +1238,9 @@ static int __cmd_record(struct record rec, int argc, const char *argv)
		goto out_child;
		}

		if (!opts->no_bpf_event)
		bpf_event__add_sb_event(&sb_evlist, &session->header.env);

		if (perf_evlist__start_sb_thread(sb_evlist, &rec->opts.target)) {
		pr_debug("Couldn't start the BPF side band thread:\nBPF programs starting from now on won't be annotatable\n");
		opts->no_bpf_event = true;

tools/perf/builtin-top.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1637,6 +1637,9 @@ int cmd_top(int argc, const char **argv)
		goto out_delete_evlist;
		}

		if (!top.record_opts.no_bpf_event)
		bpf_event__add_sb_event(&sb_evlist, &perf_env);

		if (perf_evlist__start_sb_thread(sb_evlist, target)) {
		pr_debug("Couldn't start the BPF side band thread:\nBPF programs starting from now on won't be annotatable\n");
		opts->no_bpf_event = true;

tools/perf/tests/attr/test-record-C0

+1 −1

Original line number	Diff line number	Diff line
		[config]
		command = record
		args = -C 0 kill >/dev/null 2>&1
		args = --no-bpf-event -C 0 kill >/dev/null 2>&1
		ret = 1

		[event:base-record]

tools/perf/tests/attr/test-record-basic

+1 −1

Original line number	Diff line number	Diff line
		[config]
		command = record
		args = kill >/dev/null 2>&1
		args = --no-bpf-event kill >/dev/null 2>&1
		ret = 1

		[event:base-record]

tools/perf/tests/attr/test-record-branch-any

+1 −1

Original line number	Diff line number	Diff line
		[config]
		command = record
		args = -b kill >/dev/null 2>&1
		args = --no-bpf-event -b kill >/dev/null 2>&1
		ret = 1

		[event:base-record]

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