From 1d6c9407d45dd622b277ca9f725da3cc9e95b5de Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Fri, 26 Feb 2016 09:31:55 +0000 Subject: [PATCH] perf trace: Print content of bpf-output event With this patch the contend of BPF output event is printed by 'perf trace'. For example: # ./perf trace -a --ev bpf-output/no-inherit,name=evt/ \ --ev ./test_bpf_trace.c/map:channel.event=evt/ \ usleep 100000 ... 1.787 ( 0.004 ms): usleep/3832 nanosleep(rqtp: 0x7ffc78b18980 ) ... 1.787 ( ): evt:Raise a BPF event!..) 1.788 ( ): perf_bpf_probe:func_begin:(ffffffff810e97d0)) ... 101.866 (87.038 ms): gmain/1654 poll(ufds: 0x7f57a80008c0, nfds: 2, timeout_msecs: 1000 ) ... 101.866 ( ): evt:Raise a BPF event!..) 101.867 ( ): perf_bpf_probe:func_end:(ffffffff810e97d0 <- ffffffff81796173)) 101.869 (100.087 ms): usleep/3832 ... [continued]: nanosleep()) = 0 ... (There is an extra ')' at the end of several lines. However, it is another problem, unrelated to this commit.) Where test_bpf_trace.c is: /************************ BEGIN **************************/ #include struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; }; #define SEC(NAME) __attribute__((section(NAME), used)) static u64 (*ktime_get_ns)(void) = (void *)BPF_FUNC_ktime_get_ns; static int (*trace_printk)(const char *fmt, int fmt_size, ...) = (void *)BPF_FUNC_trace_printk; static int (*get_smp_processor_id)(void) = (void *)BPF_FUNC_get_smp_processor_id; static int (*perf_event_output)(void *, struct bpf_map_def *, int, void *, unsigned long) = (void *)BPF_FUNC_perf_event_output; struct bpf_map_def SEC("maps") channel = { .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, .key_size = sizeof(int), .value_size = sizeof(u32), .max_entries = __NR_CPUS__, }; static inline int __attribute__((always_inline)) func(void *ctx, int type) { char output_str[] = "Raise a BPF event!"; char err_str[] = "BAD %d\n"; int err; err = perf_event_output(ctx, &channel, get_smp_processor_id(), &output_str, sizeof(output_str)); if (err) trace_printk(err_str, sizeof(err_str), err); return 1; } SEC("func_begin=sys_nanosleep") int func_begin(void *ctx) {return func(ctx, 1);} SEC("func_end=sys_nanosleep%return") int func_end(void *ctx) { return func(ctx, 2);} char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; /************************* END ***************************/ Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Jiri Olsa Cc: Li Zefan Cc: Peter Zijlstra Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1456479154-136027-8-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-trace.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 254149ca5e1b..26a337f939d8 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -2178,6 +2178,37 @@ out_dump: return 0; } +static void bpf_output__printer(enum binary_printer_ops op, + unsigned int val, void *extra) +{ + FILE *output = extra; + unsigned char ch = (unsigned char)val; + + switch (op) { + case BINARY_PRINT_CHAR_DATA: + fprintf(output, "%c", isprint(ch) ? ch : '.'); + break; + case BINARY_PRINT_DATA_BEGIN: + case BINARY_PRINT_LINE_BEGIN: + case BINARY_PRINT_ADDR: + case BINARY_PRINT_NUM_DATA: + case BINARY_PRINT_NUM_PAD: + case BINARY_PRINT_SEP: + case BINARY_PRINT_CHAR_PAD: + case BINARY_PRINT_LINE_END: + case BINARY_PRINT_DATA_END: + default: + break; + } +} + +static void bpf_output__fprintf(struct trace *trace, + struct perf_sample *sample) +{ + print_binary(sample->raw_data, sample->raw_size, 8, + bpf_output__printer, trace->output); +} + static int trace__event_handler(struct trace *trace, struct perf_evsel *evsel, union perf_event *event __maybe_unused, struct perf_sample *sample) @@ -2190,7 +2221,9 @@ static int trace__event_handler(struct trace *trace, struct perf_evsel *evsel, fprintf(trace->output, "%s:", evsel->name); - if (evsel->tp_format) { + if (perf_evsel__is_bpf_output(evsel)) { + bpf_output__fprintf(trace, sample); + } else if (evsel->tp_format) { event_format__fprintf(evsel->tp_format, sample->cpu, sample->raw_data, sample->raw_size, trace->output); -- 2.20.1