1

perf ftrace latency: Add -n/--use-nsec option

Sometimes we want to see nano-second granularity.

  $ sudo perf ftrace latency -T dput -a sleep 1
  #   DURATION     |      COUNT | GRAPH                          |
       0 - 1    us |    2098375 | #############################  |
       1 - 2    us |         61 |                                |
       2 - 4    us |         33 |                                |
       4 - 8    us |         13 |                                |
       8 - 16   us |        124 |                                |
      16 - 32   us |        123 |                                |
      32 - 64   us |          1 |                                |
      64 - 128  us |          0 |                                |
     128 - 256  us |          1 |                                |
     256 - 512  us |          0 |                                |
     512 - 1024 us |          0 |                                |
       1 - 2    ms |          0 |                                |
       2 - 4    ms |          0 |                                |
       4 - 8    ms |          0 |                                |
       8 - 16   ms |          0 |                                |
      16 - 32   ms |          0 |                                |
      32 - 64   ms |          0 |                                |
      64 - 128  ms |          0 |                                |
     128 - 256  ms |          0 |                                |
     256 - 512  ms |          0 |                                |
     512 - 1024 ms |          0 |                                |
       1 - ...   s |          0 |                                |

  $ sudo perf ftrace latency -T dput -a -n sleep 1
  #   DURATION     |      COUNT | GRAPH                          |
       0 - 1    us |          0 |                                |
       1 - 2    ns |          0 |                                |
       2 - 4    ns |          0 |                                |
       4 - 8    ns |          0 |                                |
       8 - 16   ns |          0 |                                |
      16 - 32   ns |          0 |                                |
      32 - 64   ns |          0 |                                |
      64 - 128  ns |    1163434 | ##############                 |
     128 - 256  ns |     914102 | #############                  |
     256 - 512  ns |        884 |                                |
     512 - 1024 ns |        613 |                                |
       1 - 2    us |         31 |                                |
       2 - 4    us |         17 |                                |
       4 - 8    us |          7 |                                |
       8 - 16   us |        123 |                                |
      16 - 32   us |         83 |                                |
      32 - 64   us |          0 |                                |
      64 - 128  us |          0 |                                |
     128 - 256  us |          0 |                                |
     256 - 512  us |          0 |                                |
     512 - 1024 us |          0 |                                |
       1 - ...  ms |          0 |                                |

Committer testing:

Testing it with BPF:

  # perf ftrace latency -b -n -T dput -a sleep 1
  #   DURATION     |      COUNT | GRAPH                                          |
       0 - 1    us |          0 |                                                |
       1 - 2    ns |          0 |                                                |
       2 - 4    ns |          0 |                                                |
       4 - 8    ns |          0 |                                                |
       8 - 16   ns |          0 |                                                |
      16 - 32   ns |          0 |                                                |
      32 - 64   ns |          0 |                                                |
      64 - 128  ns |          0 |                                                |
     128 - 256  ns |     823489 | #############################################  |
     256 - 512  ns |       3232 |                                                |
     512 - 1024 ns |         51 |                                                |
       1 - 2    us |        172 |                                                |
       2 - 4    us |          9 |                                                |
       4 - 8    us |          0 |                                                |
       8 - 16   us |          2 |                                                |
      16 - 32   us |          0 |                                                |
      32 - 64   us |          0 |                                                |
      64 - 128  us |          0 |                                                |
     128 - 256  us |          0 |                                                |
     256 - 512  us |          0 |                                                |
     512 - 1024 us |          0 |                                                |
       1 - ...  ms |          0 |                                                |
  [root@quaco ~]# strace -e bpf perf ftrace latency -b -n -T dput -a sleep 1
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_SOCKET_FILTER, insn_cnt=2, insns=0x7ffe2bd574f0, license="GPL", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0, prog_name="", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=0, func_info_rec_size=0, func_info=NULL, func_info_cnt=0, line_info_rec_size=0, line_info=NULL, line_info_cnt=0, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0\20\0\0\0\20\0\0\0\5\0\0\0\1\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=45, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0000\0\0\0000\0\0\0\t\0\0\0\1\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=81, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\08\0\0\08\0\0\0\t\0\0\0\0\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=89, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0\f\0\0\0\f\0\0\0\7\0\0\0\1\0\0\0\0\0\0\20"..., btf_log_buf=NULL, btf_size=43, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0000\0\0\0000\0\0\0\t\0\0\0\1\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=81, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0000\0\0\0000\0\0\0\5\0\0\0\0\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=77, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0(\0\0\0(\0\0\0\5\0\0\0\0\0\0\0\0\0\0\1"..., btf_log_buf=NULL, btf_size=69, btf_log_size=0, btf_log_level=0}, 28) = -1 EINVAL (Invalid argument)
  bpf(BPF_BTF_LOAD, {btf="\237\353\1\0\30\0\0\0\0\0\0\0<\3\0\0<\3\0\0\362\3\0\0\0\0\0\0\0\0\0\2"..., btf_log_buf=NULL, btf_size=1862, btf_log_size=0, btf_log_level=0}, 28) = 3
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_ARRAY, key_size=4, value_size=4, max_entries=1, map_flags=BPF_F_MMAPABLE, inner_map_fd=0, map_name="", map_ifindex=0, btf_fd=0, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 4
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_SOCKET_FILTER, insn_cnt=2, insns=0x7ffe2bd571c0, license="GPL", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0, prog_name="test", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=0, func_info_rec_size=0, func_info=NULL, func_info_cnt=0, line_info_rec_size=0, line_info=NULL, line_info_cnt=0, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 4
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=8, value_size=8, max_entries=10000, map_flags=0, inner_map_fd=0, map_name="functime", map_ifindex=0, btf_fd=3, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 4
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=4, value_size=1, max_entries=1, map_flags=0, inner_map_fd=0, map_name="cpu_filter", map_ifindex=0, btf_fd=3, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 5
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=4, value_size=1, max_entries=1, map_flags=0, inner_map_fd=0, map_name="task_filter", map_ifindex=0, btf_fd=3, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 7
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_PERCPU_ARRAY, key_size=4, value_size=8, max_entries=22, map_flags=0, inner_map_fd=0, map_name="latency", map_ifindex=0, btf_fd=3, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 8
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_ARRAY, key_size=4, value_size=32, max_entries=1, map_flags=0, inner_map_fd=0, map_name="", map_ifindex=0, btf_fd=0, btf_key_type_id=0, btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 9
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_SOCKET_FILTER, insn_cnt=5, insns=0x7ffe2bd57220, license="GPL", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0, prog_name="", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=0, func_info_rec_size=0, func_info=NULL, func_info_cnt=0, line_info_rec_size=0, line_info=NULL, line_info_cnt=0, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 10
  bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_ARRAY, key_size=4, value_size=16, max_entries=1, map_flags=BPF_F_MMAPABLE, inner_map_fd=0, map_name="func_lat.bss", map_ifindex=0, btf_fd=3, btf_key_type_id=0, btf_value_type_id=33, btf_vmlinux_value_type_id=0, map_extra=0}, 72) = 9
  bpf(BPF_MAP_UPDATE_ELEM, {map_fd=9, key=0x7ffe2bd57330, value=0x7f9a5fc39000, flags=BPF_ANY}, 144) = 0
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_KPROBE, insn_cnt=42, insns=0x113daf0, license="", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(5, 16, 13), prog_flags=0, prog_name="func_begin", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=3, func_info_rec_size=8, func_info=0x113fb70, func_info_cnt=1, line_info_rec_size=16, line_info=0x113fb90, line_info_cnt=21, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 10
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_KPROBE, insn_cnt=124, insns=0x113d360, license="", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(5, 16, 13), prog_flags=0, prog_name="func_end", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=3, func_info_rec_size=8, func_info=0x113fcf0, func_info_cnt=1, line_info_rec_size=16, line_info=0x1139770, line_info_cnt=60, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 11
  bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_TRACEPOINT, insn_cnt=2, insns=0x7ffe2bd57150, license="GPL", log_level=0, log_size=0, log_buf=NULL, kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0, prog_name="", prog_ifindex=0, expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=0, func_info_rec_size=0, func_info=NULL, func_info_cnt=0, line_info_rec_size=0, line_info=NULL, line_info_cnt=0, attach_btf_id=0, attach_prog_fd=0, fd_array=NULL}, 144) = 13
  bpf(BPF_LINK_CREATE, {link_create={prog_fd=13, target_fd=-1, attach_type=BPF_PERF_EVENT, flags=0}}, 144) = -1 EBADF (Bad file descriptor)
  bpf(BPF_LINK_CREATE, {link_create={prog_fd=10, target_fd=12, attach_type=BPF_PERF_EVENT, flags=0}}, 144) = 13
  bpf(BPF_LINK_CREATE, {link_create={prog_fd=11, target_fd=14, attach_type=BPF_PERF_EVENT, flags=0}}, 144) = 15
  --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=130075, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  bpf(BPF_MAP_LOOKUP_ELEM, {map_fd=8, key=0x7ffe2bd57624, value=0x113fdd0, flags=BPF_ANY}, 144) = 0
  #   DURATION     |      COUNT | GRAPH                                          |
       0 - 1    us |          0 |                                                |
       1 - 2    ns |          0 |                                                |
       2 - 4    ns |          0 |                                                |
       4 - 8    ns |          0 |                                                |
       8 - 16   ns |          0 |                                                |
      16 - 32   ns |          0 |                                                |
      32 - 64   ns |          0 |                                                |
      64 - 128  ns |          0 |                                                |
     128 - 256  ns |      42519 | ###########################################    |
     256 - 512  ns |       2140 | ##                                             |
     512 - 1024 ns |         54 |                                                |
       1 - 2    us |         16 |                                                |
       2 - 4    us |         10 |                                                |
       4 - 8    us |          0 |                                                |
       8 - 16   us |          0 |                                                |
      16 - 32   us |          0 |                                                |
      32 - 64   us |          0 |                                                |
      64 - 128  us |          0 |                                                |
     128 - 256  us |          0 |                                                |
     256 - 512  us |          0 |                                                |
     512 - 1024 us |          0 |                                                |
       1 - ...  ms |          0 |                                                |
  +++ exited with 0 +++
  #

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Changbin Du <changbin.du@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220321234609.90455-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2022-03-21 16:46:08 -07:00 committed by Arnaldo Carvalho de Melo
parent 7572733b84
commit 84005bb614
4 changed files with 22 additions and 11 deletions

View File

@ -680,7 +680,8 @@ out:
return (done && !workload_exec_errno) ? 0 : -1;
}
static void make_histogram(int buckets[], char *buf, size_t len, char *linebuf)
static void make_histogram(int buckets[], char *buf, size_t len, char *linebuf,
bool use_nsec)
{
char *p, *q;
char *unit;
@ -727,6 +728,9 @@ static void make_histogram(int buckets[], char *buf, size_t len, char *linebuf)
if (!unit || strncmp(unit, " us", 3))
goto next;
if (use_nsec)
num *= 1000;
i = log2(num);
if (i < 0)
i = 0;
@ -744,7 +748,7 @@ next:
strcat(linebuf, p);
}
static void display_histogram(int buckets[])
static void display_histogram(int buckets[], bool use_nsec)
{
int i;
int total = 0;
@ -770,12 +774,12 @@ static void display_histogram(int buckets[])
for (i = 1; i < NUM_BUCKET - 1; i++) {
int start = (1 << (i - 1));
int stop = 1 << i;
const char *unit = "us";
const char *unit = use_nsec ? "ns" : "us";
if (start >= 1024) {
start >>= 10;
stop >>= 10;
unit = "ms";
unit = use_nsec ? "us" : "ms";
}
bar_len = buckets[i] * bar_total / total;
printf(" %4d - %-4d %s | %10d | %.*s%*s |\n",
@ -785,8 +789,8 @@ static void display_histogram(int buckets[])
bar_len = buckets[NUM_BUCKET - 1] * bar_total / total;
printf(" %4d - %-4s %s | %10d | %.*s%*s |\n",
1, "...", " s", buckets[NUM_BUCKET - 1], bar_len, bar,
bar_total - bar_len, "");
1, "...", use_nsec ? "ms" : " s", buckets[NUM_BUCKET - 1],
bar_len, bar, bar_total - bar_len, "");
}
@ -913,7 +917,7 @@ static int __cmd_latency(struct perf_ftrace *ftrace)
if (n < 0)
break;
make_histogram(buckets, buf, n, line);
make_histogram(buckets, buf, n, line, ftrace->use_nsec);
}
}
@ -930,12 +934,12 @@ static int __cmd_latency(struct perf_ftrace *ftrace)
int n = read(trace_fd, buf, sizeof(buf) - 1);
if (n <= 0)
break;
make_histogram(buckets, buf, n, line);
make_histogram(buckets, buf, n, line, ftrace->use_nsec);
}
read_func_latency(ftrace, buckets);
display_histogram(buckets);
display_histogram(buckets, ftrace->use_nsec);
out:
close(trace_fd);
@ -1171,6 +1175,8 @@ int cmd_ftrace(int argc, const char **argv)
OPT_BOOLEAN('b', "use-bpf", &ftrace.target.use_bpf,
"Use BPF to measure function latency"),
#endif
OPT_BOOLEAN('n', "--use-nsec", &ftrace.use_nsec,
"Use nano-second histogram"),
OPT_PARENT(common_options),
};
const struct option *options = ftrace_options;

View File

@ -81,6 +81,8 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
}
}
skel->bss->use_nsec = ftrace->use_nsec;
skel->links.func_begin = bpf_program__attach_kprobe(skel->progs.func_begin,
false, func->name);
if (IS_ERR(skel->links.func_begin)) {

View File

@ -39,6 +39,7 @@ struct {
int enabled = 0;
int has_cpu = 0;
int has_task = 0;
int use_nsec = 0;
SEC("kprobe/func")
int BPF_PROG(func_begin)
@ -80,6 +81,7 @@ int BPF_PROG(func_end)
{
__u64 tid;
__u64 *start;
__u64 cmp_base = use_nsec ? 1 : 1000;
if (!enabled)
return 0;
@ -97,9 +99,9 @@ int BPF_PROG(func_end)
if (delta < 0)
return 0;
// calculate index using delta in usec
// calculate index using delta
for (key = 0; key < (NUM_BUCKET - 1); key++) {
if (delta < ((1000UL) << key))
if (delta < (cmp_base << key))
break;
}

View File

@ -17,6 +17,7 @@ struct perf_ftrace {
struct list_head nograph_funcs;
unsigned long percpu_buffer_size;
bool inherit;
bool use_nsec;
int graph_depth;
int func_stack_trace;
int func_irq_info;