From 03e0a7df3efd959e40cd7ff40b1fabddc234ec5a Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 22 Feb 2016 09:10:37 +0000 Subject: perf tools: Introduce bpf-output event Commit a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") adds a helper to enable a BPF program to output data to a perf ring buffer through a new type of perf event, PERF_COUNT_SW_BPF_OUTPUT. This patch enables perf to create events of that type. Now a perf user can use the following cmdline to receive output data from BPF programs: # perf record -a -e bpf-output/no-inherit,name=evt/ \ -e ./test_bpf_output.c/map:channel.event=evt/ ls / # perf script perf 1560 [004] 347747.086295: evt: ffffffff811fd201 sys_write ... perf 1560 [004] 347747.086300: evt: ffffffff811fd201 sys_write ... perf 1560 [004] 347747.086315: evt: ffffffff811fd201 sys_write ... ... Test result: # cat test_bpf_output.c /************************ 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__, }; SEC("func_write=sys_write") int func_write(void *ctx) { struct { u64 ktime; int cpuid; } __attribute__((packed)) output_data; char error_data[] = "Error: failed to output: %d\n"; output_data.cpuid = get_smp_processor_id(); output_data.ktime = ktime_get_ns(); int err = perf_event_output(ctx, &channel, get_smp_processor_id(), &output_data, sizeof(output_data)); if (err) trace_printk(error_data, sizeof(error_data), err); return 0; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; /************************ END ***************************/ # perf record -a -e bpf-output/no-inherit,name=evt/ \ -e ./test_bpf_output.c/map:channel.event=evt/ ls / # perf script | grep ls ls 2242 [003] 347851.557563: evt: ffffffff811fd201 sys_write ... ls 2242 [003] 347851.557571: evt: ffffffff811fd201 sys_write ... Signed-off-by: Wang Nan Cc: Adrian Hunter Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Cody P Schafer Cc: He Kuang Cc: Jeremie Galarneau Cc: Jiri Olsa Cc: Kirill Smelkov Cc: Li Zefan Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1456132275-98875-11-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'tools/perf/util/bpf-loader.c') diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 44824e3eeaed..0967ce601931 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -1331,13 +1331,12 @@ apply_config_evsel_for_key(const char *name, int map_fd, void *pkey, return -BPF_LOADER_ERRNO__OBJCONF_MAP_EVTINH; } + if (perf_evsel__is_bpf_output(evsel)) + check_pass = true; if (attr->type == PERF_TYPE_RAW) check_pass = true; if (attr->type == PERF_TYPE_HARDWARE) check_pass = true; - if (attr->type == PERF_TYPE_SOFTWARE && - attr->config == PERF_COUNT_SW_BPF_OUTPUT) - check_pass = true; if (!check_pass) { pr_debug("ERROR: Event type is wrong for map %s\n", name); return -BPF_LOADER_ERRNO__OBJCONF_MAP_EVTTYPE; -- cgit v1.2.3