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Subject[tip:perf/core] perf tools: Handle PERF_RECORD_BPF_EVENT
Commit-ID:  45178a928a4b7c6093f6621e627d09909e81cc13
Gitweb: https://git.kernel.org/tip/45178a928a4b7c6093f6621e627d09909e81cc13
Author: Song Liu <songliubraving@fb.com>
AuthorDate: Thu, 17 Jan 2019 08:15:18 -0800
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 21 Jan 2019 17:00:57 -0300

perf tools: Handle PERF_RECORD_BPF_EVENT

This patch adds basic handling of PERF_RECORD_BPF_EVENT. Tracking of
PERF_RECORD_BPF_EVENT is OFF by default. Option --bpf-event is added to
turn it on.

Committer notes:

Add dummy machine__process_bpf_event() variant that returns zero for
systems without HAVE_LIBBPF_SUPPORT, such as Alpine Linux, unbreaking
the build in such systems.

Remove the needless include <machine.h> from bpf->event.h, provide just
forward declarations for the structs and unions in the parameters, to
reduce compilation time and needless rebuilds when machine.h gets
changed.

Committer testing:

When running with:

# perf record --bpf-event

On an older kernel where PERF_RECORD_BPF_EVENT and PERF_RECORD_KSYMBOL
is not present, we fallback to removing those two bits from
perf_event_attr, making the tool to continue to work on older kernels:

perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
ksymbol 1
bpf_event 1
------------------------------------------------------------
sys_perf_event_open: pid 5779 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off bpf_event
------------------------------------------------------------
perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
ksymbol 1
------------------------------------------------------------
sys_perf_event_open: pid 5779 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off ksymbol
------------------------------------------------------------
perf_event_attr:
size 112
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|PERIOD
read_format ID
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
precise_ip 3
sample_id_all 1
exclude_guest 1
mmap2 1
comm_exec 1
------------------------------------------------------------

And then proceeds to work without those two features.

As passing --bpf-event is an explicit action performed by the user, perhaps we
should emit a warning telling that the kernel has no such feature, but this can
be done on top of this patch.

Now with a kernel that supports these events, start the 'record --bpf-event -a'
and then run 'perf trace sleep 10000' that will use the BPF
augmented_raw_syscalls.o prebuilt (for another kernel version even) and thus
should generate PERF_RECORD_BPF_EVENT events:

[root@quaco ~]# perf record -e dummy -a --bpf-event
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.713 MB perf.data ]

[root@quaco ~]# bpftool prog
13: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 13,14
14: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 13,14
15: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 15,16
16: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:43-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 15,16
17: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:44-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 17,18
18: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:44-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 17,18
21: cgroup_skb tag 7be49e3934a125ba gpl
loaded_at 2019-01-19T09:09:45-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 21,22
22: cgroup_skb tag 2a142ef67aaad174 gpl
loaded_at 2019-01-19T09:09:45-0300 uid 0
xlated 296B jited 229B memlock 4096B map_ids 21,22
31: tracepoint name sys_enter tag 12504ba9402f952f gpl
loaded_at 2019-01-19T09:19:56-0300 uid 0
xlated 512B jited 374B memlock 4096B map_ids 30,29,28
32: tracepoint name sys_exit tag c1bd85c092d6e4aa gpl
loaded_at 2019-01-19T09:19:56-0300 uid 0
xlated 256B jited 191B memlock 4096B map_ids 30,29
# perf report -D | grep PERF_RECORD_BPF_EVENT | nl
1 0 55834574849 0x4fc8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 13
2 0 60129542145 0x5118 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 14
3 0 64424509441 0x5268 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 15
4 0 68719476737 0x53b8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 16
5 0 73014444033 0x5508 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 17
6 0 77309411329 0x5658 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 18
7 0 90194313217 0x57a8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 21
8 0 94489280513 0x58f8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 22
9 7 620922484360 0xb6390 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 29
10 7 620922486018 0xb6410 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 29
11 7 620922579199 0xb6490 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 30
12 7 620922580240 0xb6510 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 30
13 7 620922765207 0xb6598 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 31
14 7 620922874543 0xb6620 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 32
#

There, the 31 and 32 tracepoint BPF programs put in place by 'perf trace'.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-7-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 1 +
tools/perf/perf.h | 1 +
tools/perf/util/Build | 2 ++
tools/perf/util/bpf-event.c | 15 +++++++++++++++
tools/perf/util/bpf-event.h | 22 ++++++++++++++++++++++
tools/perf/util/event.c | 20 ++++++++++++++++++++
tools/perf/util/event.h | 16 ++++++++++++++++
tools/perf/util/evsel.c | 11 ++++++++++-
tools/perf/util/evsel.h | 1 +
tools/perf/util/machine.c | 3 +++
tools/perf/util/session.c | 4 ++++
tools/perf/util/tool.h | 3 ++-
12 files changed, 97 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 882285fb9f64..deaf9b902094 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1839,6 +1839,7 @@ static struct option __record_options[] = {
OPT_BOOLEAN(0, "tail-synthesize", &record.opts.tail_synthesize,
"synthesize non-sample events at the end of output"),
OPT_BOOLEAN(0, "overwrite", &record.opts.overwrite, "use overwrite mode"),
+ OPT_BOOLEAN(0, "bpf-event", &record.opts.bpf_event, "record bpf events"),
OPT_BOOLEAN(0, "strict-freq", &record.opts.strict_freq,
"Fail if the specified frequency can't be used"),
OPT_CALLBACK('F', "freq", &record.opts, "freq or 'max'",
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 388c6dd128b8..5941fb6eccfc 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -66,6 +66,7 @@ struct record_opts {
bool ignore_missing_thread;
bool strict_freq;
bool sample_id;
+ bool bpf_event;
unsigned int freq;
unsigned int mmap_pages;
unsigned int auxtrace_mmap_pages;
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 3ad6a800948d..c359af408334 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -154,6 +154,8 @@ endif

libperf-y += perf-hooks.o

+libperf-$(CONFIG_LIBBPF) += bpf-event.o
+
libperf-$(CONFIG_CXX) += c++/

CFLAGS_config.o += -DETC_PERFCONFIG="BUILD_STR($(ETC_PERFCONFIG_SQ))"
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
new file mode 100644
index 000000000000..87004706874f
--- /dev/null
+++ b/tools/perf/util/bpf-event.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <bpf/bpf.h>
+#include "bpf-event.h"
+#include "debug.h"
+#include "symbol.h"
+
+int machine__process_bpf_event(struct machine *machine __maybe_unused,
+ union perf_event *event,
+ struct perf_sample *sample __maybe_unused)
+{
+ if (dump_trace)
+ perf_event__fprintf_bpf_event(event, stdout);
+ return 0;
+}
diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
new file mode 100644
index 000000000000..da0dfc035fc6
--- /dev/null
+++ b/tools/perf/util/bpf-event.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_BPF_EVENT_H
+#define __PERF_BPF_EVENT_H
+
+#include <linux/compiler.h>
+
+struct machine;
+union perf_event;
+struct perf_sample;
+
+#ifdef HAVE_LIBBPF_SUPPORT
+int machine__process_bpf_event(struct machine *machine, union perf_event *event,
+ struct perf_sample *sample);
+#else
+static inline int machine__process_bpf_event(struct machine *machine __maybe_unused,
+ union perf_event *event __maybe_unused,
+ struct perf_sample *sample __maybe_unused)
+{
+ return 0;
+}
+#endif // HAVE_LIBBPF_SUPPORT
+#endif
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index f06f3811b25b..1b5091a3d14f 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -25,6 +25,7 @@
#include "asm/bug.h"
#include "stat.h"
#include "session.h"
+#include "bpf-event.h"

#define DEFAULT_PROC_MAP_PARSE_TIMEOUT 500

@@ -47,6 +48,7 @@ static const char *perf_event__names[] = {
[PERF_RECORD_SWITCH_CPU_WIDE] = "SWITCH_CPU_WIDE",
[PERF_RECORD_NAMESPACES] = "NAMESPACES",
[PERF_RECORD_KSYMBOL] = "KSYMBOL",
+ [PERF_RECORD_BPF_EVENT] = "BPF_EVENT",
[PERF_RECORD_HEADER_ATTR] = "ATTR",
[PERF_RECORD_HEADER_EVENT_TYPE] = "EVENT_TYPE",
[PERF_RECORD_HEADER_TRACING_DATA] = "TRACING_DATA",
@@ -1339,6 +1341,14 @@ int perf_event__process_ksymbol(struct perf_tool *tool __maybe_unused,
return machine__process_ksymbol(machine, event, sample);
}

+int perf_event__process_bpf_event(struct perf_tool *tool __maybe_unused,
+ union perf_event *event,
+ struct perf_sample *sample __maybe_unused,
+ struct machine *machine)
+{
+ return machine__process_bpf_event(machine, event, sample);
+}
+
size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp)
{
return fprintf(fp, " %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64 "]: %c %s\n",
@@ -1479,6 +1489,13 @@ size_t perf_event__fprintf_ksymbol(union perf_event *event, FILE *fp)
event->ksymbol_event.flags, event->ksymbol_event.name);
}

+size_t perf_event__fprintf_bpf_event(union perf_event *event, FILE *fp)
+{
+ return fprintf(fp, " bpf event with type %u, flags %u, id %u\n",
+ event->bpf_event.type, event->bpf_event.flags,
+ event->bpf_event.id);
+}
+
size_t perf_event__fprintf(union perf_event *event, FILE *fp)
{
size_t ret = fprintf(fp, "PERF_RECORD_%s",
@@ -1517,6 +1534,9 @@ size_t perf_event__fprintf(union perf_event *event, FILE *fp)
case PERF_RECORD_KSYMBOL:
ret += perf_event__fprintf_ksymbol(event, fp);
break;
+ case PERF_RECORD_BPF_EVENT:
+ ret += perf_event__fprintf_bpf_event(event, fp);
+ break;
default:
ret += fprintf(fp, "\n");
}
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 018322f2a13e..dad32b81fe71 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -98,6 +98,16 @@ struct ksymbol_event {
char name[KSYM_NAME_LEN];
};

+struct bpf_event {
+ struct perf_event_header header;
+ u16 type;
+ u16 flags;
+ u32 id;
+
+ /* for bpf_prog types */
+ u8 tag[BPF_TAG_SIZE]; // prog tag
+};
+
#define PERF_SAMPLE_MASK \
(PERF_SAMPLE_IP | PERF_SAMPLE_TID | \
PERF_SAMPLE_TIME | PERF_SAMPLE_ADDR | \
@@ -666,6 +676,7 @@ union perf_event {
struct time_conv_event time_conv;
struct feature_event feat;
struct ksymbol_event ksymbol_event;
+ struct bpf_event bpf_event;
};

void perf_event__print_totals(void);
@@ -767,6 +778,10 @@ int perf_event__process_ksymbol(struct perf_tool *tool,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine);
+int perf_event__process_bpf_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct machine *machine);
int perf_tool__process_synth_event(struct perf_tool *tool,
union perf_event *event,
struct machine *machine,
@@ -831,6 +846,7 @@ size_t perf_event__fprintf_thread_map(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_cpu_map(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_namespaces(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_ksymbol(union perf_event *event, FILE *fp);
+size_t perf_event__fprintf_bpf_event(union perf_event *event, FILE *fp);
size_t perf_event__fprintf(union perf_event *event, FILE *fp);

int kallsyms__get_function_start(const char *kallsyms_filename,
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 9c8dc6d1aa7f..684c893ca6bc 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1036,6 +1036,8 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts,
attr->mmap2 = track && !perf_missing_features.mmap2;
attr->comm = track;
attr->ksymbol = track && !perf_missing_features.ksymbol;
+ attr->bpf_event = track && opts->bpf_event &&
+ !perf_missing_features.bpf_event;

if (opts->record_namespaces)
attr->namespaces = track;
@@ -1654,6 +1656,7 @@ int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
PRINT_ATTRf(write_backward, p_unsigned);
PRINT_ATTRf(namespaces, p_unsigned);
PRINT_ATTRf(ksymbol, p_unsigned);
+ PRINT_ATTRf(bpf_event, p_unsigned);

PRINT_ATTRn("{ wakeup_events, wakeup_watermark }", wakeup_events, p_unsigned);
PRINT_ATTRf(bp_type, p_unsigned);
@@ -1815,6 +1818,8 @@ fallback_missing_features:
evsel->attr.read_format &= ~(PERF_FORMAT_GROUP|PERF_FORMAT_ID);
if (perf_missing_features.ksymbol)
evsel->attr.ksymbol = 0;
+ if (perf_missing_features.bpf_event)
+ evsel->attr.bpf_event = 0;
retry_sample_id:
if (perf_missing_features.sample_id_all)
evsel->attr.sample_id_all = 0;
@@ -1934,7 +1939,11 @@ try_fallback:
* Must probe features in the order they were added to the
* perf_event_attr interface.
*/
- if (!perf_missing_features.ksymbol && evsel->attr.ksymbol) {
+ if (!perf_missing_features.bpf_event && evsel->attr.bpf_event) {
+ perf_missing_features.bpf_event = true;
+ pr_debug2("switching off bpf_event\n");
+ goto fallback_missing_features;
+ } else if (!perf_missing_features.ksymbol && evsel->attr.ksymbol) {
perf_missing_features.ksymbol = true;
pr_debug2("switching off ksymbol\n");
goto fallback_missing_features;
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 4a8c3e7f4808..29c5eb68c44b 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -169,6 +169,7 @@ struct perf_missing_features {
bool write_backward;
bool group_read;
bool ksymbol;
+ bool bpf_event;
};

extern struct perf_missing_features perf_missing_features;
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 9bca61c7d5bf..ae85106bb5bf 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -21,6 +21,7 @@
#include "unwind.h"
#include "linux/hash.h"
#include "asm/bug.h"
+#include "bpf-event.h"

#include "sane_ctype.h"
#include <symbol/kallsyms.h>
@@ -1867,6 +1868,8 @@ int machine__process_event(struct machine *machine, union perf_event *event,
ret = machine__process_switch_event(machine, event); break;
case PERF_RECORD_KSYMBOL:
ret = machine__process_ksymbol(machine, event, sample); break;
+ case PERF_RECORD_BPF_EVENT:
+ ret = machine__process_bpf_event(machine, event, sample); break;
default:
ret = -1;
break;
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index dcfacfb036a3..24fd62528a33 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -381,6 +381,8 @@ void perf_tool__fill_defaults(struct perf_tool *tool)
tool->context_switch = perf_event__process_switch;
if (tool->ksymbol == NULL)
tool->ksymbol = perf_event__process_ksymbol;
+ if (tool->bpf_event == NULL)
+ tool->bpf_event = perf_event__process_bpf_event;
if (tool->read == NULL)
tool->read = process_event_sample_stub;
if (tool->throttle == NULL)
@@ -1314,6 +1316,8 @@ static int machines__deliver_event(struct machines *machines,
return tool->context_switch(tool, event, sample, machine);
case PERF_RECORD_KSYMBOL:
return tool->ksymbol(tool, event, sample, machine);
+ case PERF_RECORD_BPF_EVENT:
+ return tool->bpf_event(tool, event, sample, machine);
default:
++evlist->stats.nr_unknown_events;
return -1;
diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
index 9c81ca2f3cf7..250391672f9f 100644
--- a/tools/perf/util/tool.h
+++ b/tools/perf/util/tool.h
@@ -54,7 +54,8 @@ struct perf_tool {
context_switch,
throttle,
unthrottle,
- ksymbol;
+ ksymbol,
+ bpf_event;

event_attr_op attr;
event_attr_op event_update;
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