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authorArnaldo Carvalho de Melo <acme@redhat.com>2019-02-19 16:17:33 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-02-19 16:35:45 -0300
commitff7a4f98d52cd3f13b1f4f6f22208498b0c113f7 (patch)
treee98e852c537459f89057d81a0e67efc5e2b4a2ec
parentd19f856479feef7c1383f02b87688563a0ef7a14 (diff)
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.hunter@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Yonghong Song <yhs@fb.com> Link: https://lkml.kernel.org/n/tip-ztxj25rtx37ixo9cfajt8ocy@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/Documentation/perf-trace.txt8
-rw-r--r--tools/perf/builtin-trace.c19
2 files changed, 27 insertions, 0 deletions
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;