From e571e029bdbf59f485fe67740b7a4ef421e1d55d Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 22 Feb 2016 09:10:35 +0000 Subject: perf tools: Enable indices setting syntax for BPF map This patch introduces a new syntax to perf event parser: # perf record -e './test_bpf_map_3.c/map:channel.value[0,1,2,3...5]=101/' usleep 2 By utilizing the basic facilities in bpf-loader.c which allow setting different slots in a BPF map separately, the newly introduced syntax allows perf to control specific elements in a BPF map. Test result: # cat ./test_bpf_map_3.c /************************ BEGIN **************************/ #include #define SEC(NAME) __attribute__((section(NAME), used)) struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; }; static void *(*map_lookup_elem)(struct bpf_map_def *, void *) = (void *)BPF_FUNC_map_lookup_elem; static int (*trace_printk)(const char *fmt, int fmt_size, ...) = (void *)BPF_FUNC_trace_printk; struct bpf_map_def SEC("maps") channel = { .type = BPF_MAP_TYPE_ARRAY, .key_size = sizeof(int), .value_size = sizeof(unsigned char), .max_entries = 100, }; SEC("func=hrtimer_nanosleep rqtp->tv_nsec") int func(void *ctx, int err, long nsec) { char fmt[] = "%ld\n"; long usec = nsec * 0x10624dd3 >> 38; // nsec / 1000 int key = (int)usec; unsigned char *pval = map_lookup_elem(&channel, &key); if (!pval) return 0; trace_printk(fmt, sizeof(fmt), (unsigned char)*pval); return 0; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; /************************* END ***************************/ Normal case: # echo "" > /sys/kernel/debug/tracing/trace # ./perf record -e './test_bpf_map_3.c/map:channel.value[0,1,2,3...5]=101/' usleep 2 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.012 MB perf.data ] # cat /sys/kernel/debug/tracing/trace | grep usleep usleep-405 [004] d... 2745423.547822: : 101 # ./perf record -e './test_bpf_map_3.c/map:channel.value[0...9,20...29]=102,map:channel.value[10...19]=103/' usleep 3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.012 MB perf.data ] # ./perf record -e './test_bpf_map_3.c/map:channel.value[0...9,20...29]=102,map:channel.value[10...19]=103/' usleep 15 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.012 MB perf.data ] # cat /sys/kernel/debug/tracing/trace | grep usleep usleep-405 [004] d... 2745423.547822: : 101 usleep-655 [006] d... 2745434.122814: : 102 usleep-904 [006] d... 2745439.916264: : 103 # ./perf record -e './test_bpf_map_3.c/map:channel.value[all]=104/' usleep 99 # cat /sys/kernel/debug/tracing/trace | grep usleep usleep-405 [004] d... 2745423.547822: : 101 usleep-655 [006] d... 2745434.122814: : 102 usleep-904 [006] d... 2745439.916264: : 103 usleep-1537 [003] d... 2745538.053737: : 104 Error case: # ./perf record -e './test_bpf_map_3.c/map:channel.value[10...1000]=104/' usleep 99 event syntax error: '..annel.value[10...1000]=104/' \___ Index too large Hint: Valid config terms: map:[].value=[value] map:[].event=[event] where is something like [0,3...5] or [all] (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [] [] or: perf record [] -- [] -e, --event event selector. use 'perf list' to list available events Signed-off-by: Wang Nan Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Cody P Schafer Cc: He Kuang Cc: Jeremie Galarneau 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/1456132275-98875-9-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/parse-events.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'tools/perf/util/parse-events.c') diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 697d3506c584..6e2f20334379 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -704,9 +704,10 @@ parse_events_config_bpf(struct parse_events_evlist *data, sizeof(errbuf)); data->error->help = strdup( "Hint:\tValid config terms:\n" -" \tmap:[].value=[value]\n" -" \tmap:[].event=[event]\n" +" \tmap:[].value=[value]\n" +" \tmap:[].event=[event]\n" "\n" +" \twhere is something like [0,3...5] or [all]\n" " \t(add -v to see detail)"); data->error->str = strdup(errbuf); if (err == -BPF_LOADER_ERRNO__OBJCONF_MAP_VALUE) -- cgit v1.2.3