From ff7a4f98d52cd3f13b1f4f6f22208498b0c113f7 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 19 Feb 2019 16:17:33 -0300 Subject: [PATCH] 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 Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Jiri Olsa Cc: Martin KaFai Lau Cc: Namhyung Kim Cc: Yonghong Song Link: https://lkml.kernel.org/n/tip-ztxj25rtx37ixo9cfajt8ocy@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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 #include #include +#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; -- 2.30.2