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Subject[tip: perf/urgent] perf script: Introduce --deltatime option
The following commit has been merged into the perf/urgent branch of tip:

Commit-ID: 26567ed79d13ec54b2c5661ce8a07fd149a23a9b
Gitweb: https://git.kernel.org/tip/26567ed79d13ec54b2c5661ce8a07fd149a23a9b
Author: Hagen Paul Pfeifer <hagen@jauu.net>
AuthorDate: Tue, 04 Feb 2020 18:37:09 +01:00
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitterDate: Fri, 27 Mar 2020 10:38:47 -03:00

perf script: Introduce --deltatime option

For some kind of analysis a deltatime output is more human friendly and
reduce the cognitive load for further analysis.

The following output demonstrate the new option "deltatime": calculate
the time difference in relation to the previous event.

$ perf script --deltatime
test 2525 [001] 0.000000: sdt_libev:ev_add: (5635e72a5ebd)
test 2525 [001] 0.000091: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 1.000051: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
test 2525 [001] 0.000685: sdt_libev:ev_add: (5635e72a5ebd)
test 2525 [001] 0.000048: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 1.000104: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
test 2525 [001] 0.003895: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 0.996034: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
test 2525 [001] 0.000058: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 1.000004: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
test 2525 [001] 0.000064: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 0.999934: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
test 2525 [001] 0.000056: sdt_libev:epoll_wait_enter: (5635e72a76a9)
test 2525 [001] 0.999930: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1

Committer testing:

So go from default output to --reltime and then this new --deltatime, to
contrast the various timestamp presentation modes for a random perf.data file I
had laying around:

[root@five ~]# perf script --reltime | head
perf 442394 [000] 0.000000: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000002: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000004: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000006: 128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000009: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000036: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000038: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000040: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000041: 224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000044: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
[root@five ~]# perf script --deltatime | head
perf 442394 [000] 0.000000: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000002: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000001: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000001: 128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 0.000002: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000027: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000002: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000001: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000001: 224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 0.000002: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
[root@five ~]# perf script | head
perf 442394 [000] 7600.157861: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 7600.157864: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 7600.157866: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 7600.157867: 128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [000] 7600.157870: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 7600.157897: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 7600.157900: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 7600.157901: 16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 7600.157903: 224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
perf 442394 [001] 7600.157906: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
[root@five ~]#

Andi suggested we better implement it as a new field, i.e. -F deltatime, like:

[root@five ~]# perf script -F deltatime
Invalid field requested.

Usage: perf script [<options>]
or: perf script [<options>] record <script> [<record-options>] <command>
or: perf script [<options>] report <script> [script-args]
or: perf script [<options>] <script> [<record-options>] <command>
or: perf script [<options>] <top-script> [script-args]

-F, --fields <str> comma separated output fields prepend with 'type:'. +field to add and -field to remove.Valid types: hw,sw,trace,raw,synth. Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr,symoff,srcline,period,iregs,uregs,brstack,brstacksym,flags,bpf-output,brstackinsn,brstackoff,callindent,insn,insnlen,synth,phys_addr,metric,misc,ipc
[root@five ~]#

I.e. we have -F for maximum flexibility:

[root@five ~]# perf script -F comm,pid,cpu,time | head
perf 442394 [000] 7600.157861:
perf 442394 [000] 7600.157864:
perf 442394 [000] 7600.157866:
perf 442394 [000] 7600.157867:
perf 442394 [000] 7600.157870:
perf 442394 [001] 7600.157897:
perf 442394 [001] 7600.157900:
perf 442394 [001] 7600.157901:
perf 442394 [001] 7600.157903:
perf 442394 [001] 7600.157906:
[root@five ~]#

But since we already have --reltime, having --deltatime, documented one after
the other is sensible.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20200204173709.489161-1-hagen@jauu.net
[ Added 'perf script' man page entry for --deltatime ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-script.txt | 3 +++
tools/perf/builtin-script.c | 17 +++++++++++++++++
2 files changed, 20 insertions(+)

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index db6a36a..4af255b 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -390,6 +390,9 @@ include::itrace.txt[]
--reltime::
Print time stamps relative to trace start.

+--deltatime::
+ Print time stamps relative to previous event.
+
--per-event-dump::
Create per event files with a "perf.data.EVENT.dump" name instead of
printing to stdout, useful, for instance, for generating flamegraphs.
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 656b347..f63869a 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -63,7 +63,9 @@
static char const *script_name;
static char const *generate_script_lang;
static bool reltime;
+static bool deltatime;
static u64 initial_time;
+static u64 previous_time;
static bool debug_mode;
static u64 last_timestamp;
static u64 nr_unordered;
@@ -704,6 +706,13 @@ static int perf_sample__fprintf_start(struct perf_sample *sample,
if (!initial_time)
initial_time = sample->time;
t = sample->time - initial_time;
+ } else if (deltatime) {
+ if (previous_time)
+ t = sample->time - previous_time;
+ else {
+ t = 0;
+ }
+ previous_time = sample->time;
}
nsecs = t;
secs = nsecs / NSEC_PER_SEC;
@@ -3555,6 +3564,7 @@ int cmd_script(int argc, const char **argv)
"anything beyond the specified depth will be ignored. "
"Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)),
OPT_BOOLEAN(0, "reltime", &reltime, "Show time stamps relative to start"),
+ OPT_BOOLEAN(0, "deltatime", &deltatime, "Show time stamps relative to previous event"),
OPT_BOOLEAN('I', "show-info", &show_full_info,
"display extended information from perf.data file"),
OPT_BOOLEAN('\0', "show-kernel-path", &symbol_conf.show_kernel_path,
@@ -3651,6 +3661,13 @@ int cmd_script(int argc, const char **argv)
}
}

+ if (reltime && deltatime) {
+ fprintf(stderr,
+ "reltime and deltatime - the two don't get along well. "
+ "Please limit to --reltime or --deltatime.\n");
+ return -1;
+ }
+
if (itrace_synth_opts.callchain &&
itrace_synth_opts.callchain_sz > scripting_max_stack)
scripting_max_stack = itrace_synth_opts.callchain_sz;
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