Commit-ID: ff7a4f98d52cd3f13b1f4f6f22208498b0c113f7
Gitweb: https://git.kernel.org/tip/ff7a4f98d52cd3f13b1f4f6f22208498b0c113f7
Author: Arnaldo Carvalho de Melo <a...@redhat.com>
AuthorDate: Tue, 19 Feb 2019 16:17:33 -0300
Committer: Arnaldo Carvalho de Melo <a...@redhat.com>
CommitDate: Tue, 19 Feb 2019 16:35:45 -0300
perf trace: Allow dumping a BPF map after setting up BPF events
Initial use case:
Dumping the maps setup by tools/perf/examples/bpf/augmented_raw_syscalls.c,
which so far are just booleans, showing just non-zeroed entries:
# cat ~/.perfconfig
[llvm]
dump-obj = true
clang-opt = -g
[trace]
#add_events =
/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
add_events = /wb/augmented_raw_syscalls.o
$ date
Tue Feb 19 16:29:33 -03 2019
$ ls -la /wb/augmented_raw_syscalls.o
-rwxr-xr-x. 1 root root 14048 Jan 24 12:09 /wb/augmented_raw_syscalls.o
$ file /wb/augmented_raw_syscalls.o
/wb/augmented_raw_syscalls.o: ELF 64-bit LSB relocatable, eBPF, version 1
(SYSV), with debug_info, not stripped
$
# trace -e recvmmsg,sendmmsg --map-dump foobar
ERROR: BPF map "foobar" not found
# trace -e recvmmsg,sendmmsg --map-dump filtered_pids
ERROR: BPF map "filtered_pids" not found
# trace -e recvmmsg,sendmmsg --map-dump pids_filtered
[2583] = 1,
[2267] = 1,
^Z
[1]+ Stopped trace -e recvmmsg,sendmmsg --map-dump
pids_filtered
# pidof trace
2267
# ps ax|grep gnome-terminal|grep -v grep
2583 ? Ssl 58:33 /usr/libexec/gnome-terminal-server
^C
# trace -e recvmmsg,sendmmsg --map-dump syscalls
[299] = 1,
[307] = 1,
^C
# grep x64_recvmmsg arch/x86/entry/syscalls/syscall_64.tbl
299 64 recvmmsg __x64_sys_recvmmsg
# grep x64_sendmmsg arch/x86/entry/syscalls/syscall_64.tbl
307 64 sendmmsg __x64_sys_sendmmsg
#
Next step probably will be something like 'perf stat's --interval-print and
--interval-clear.
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Martin KaFai Lau <ka...@fb.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Yonghong Song <y...@fb.com>
Link: https://lkml.kernel.org/n/tip-ztxj25rtx37ixo9cfajt8...@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
tools/perf/Documentation/perf-trace.txt | 8 ++++++++
tools/perf/builtin-trace.c | 19 +++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/tools/perf/Documentation/perf-trace.txt
b/tools/perf/Documentation/perf-trace.txt
index 631e687be4eb..fc6e43262c41 100644
--- a/tools/perf/Documentation/perf-trace.txt
+++ b/tools/perf/Documentation/perf-trace.txt
@@ -210,6 +210,14 @@ the thread executes on the designated CPUs. Default is to
monitor all CPUs.
may happen, for instance, when a thread gets migrated to a different CPU
while processing a syscall.
+--map-dump::
+ Dump BPF maps setup by events passed via -e, for instance the
augmented_raw_syscalls
+ living in tools/perf/examples/bpf/augmented_raw_syscalls.c. For now this
+ dumps just boolean map values and integer keys, in time this will print
in hex
+ by default and use BTF when available, as well as use functions to do
pretty
+ printing using the existing 'perf trace' syscall arg beautifiers to map
integer
+ arguments to strings (pid to comm, syscall id to syscall name, etc).
+
PAGEFAULTS
----------
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 68a01e624ad3..1a11fe656afc 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -19,6 +19,7 @@
#include <traceevent/event-parse.h>
#include <api/fs/tracing_path.h>
#include <bpf/bpf.h>
+#include "util/bpf_map.h"
#include "builtin.h"
#include "util/cgroup.h"
#include "util/color.h"
@@ -87,6 +88,9 @@ struct trace {
*augmented;
} events;
} syscalls;
+ struct {
+ struct bpf_map *map;
+ } dump;
struct record_opts opts;
struct perf_evlist *evlist;
struct machine *host;
@@ -2997,6 +3001,9 @@ static int trace__run(struct trace *trace, int argc,
const char **argv)
if (err < 0)
goto out_error_apply_filters;
+ if (trace->dump.map)
+ bpf_map__fprintf(trace->dump.map, trace->output);
+
err = perf_evlist__mmap(evlist, trace->opts.mmap_pages);
if (err < 0)
goto out_error_mmap;
@@ -3686,6 +3693,7 @@ int cmd_trace(int argc, const char **argv)
.max_stack = UINT_MAX,
.max_events = ULONG_MAX,
};
+ const char *map_dump_str = NULL;
const char *output_name = NULL;
const struct option trace_options[] = {
OPT_CALLBACK('e', "event", &trace, "event",
@@ -3718,6 +3726,9 @@ int cmd_trace(int argc, const char **argv)
OPT_CALLBACK(0, "duration", &trace, "float",
"show only events with duration > N.M ms",
trace__set_duration),
+#ifdef HAVE_LIBBPF_SUPPORT
+ OPT_STRING(0, "map-dump", &map_dump_str, "BPF map", "BPF map to
periodically dump"),
+#endif
OPT_BOOLEAN(0, "sched", &trace.sched, "show blocking scheduler events"),
OPT_INCR('v', "verbose", &verbose, "be more verbose"),
OPT_BOOLEAN('T', "time", &trace.full_time,
@@ -3812,6 +3823,14 @@ int cmd_trace(int argc, const char **argv)
err = -1;
+ if (map_dump_str) {
+ trace.dump.map = bpf__find_map_by_name(map_dump_str);
+ if (trace.dump.map == NULL) {
+ pr_err("ERROR: BPF map \"%s\" not found\n",
map_dump_str);
+ goto out;
+ }
+ }
+
if (trace.trace_pgfaults) {
trace.opts.sample_address = true;
trace.opts.sample_time = true;
