[PATCH 14/17] perf report: Add --switch-on/--switch-off events

Arnaldo Carvalho de Melo
2019-08-16T20:18:14Z

Since 'perf top' shares the histogram browser with 'perf report', then
the same explanation in the previous cset applies.

An additional example uses a pair of SDT events available for systemtap:

# perf probe --exec=/usr/bin/stap '%*:*'
Added new events:
sdt_stap:benchmark__thread__start (on %* in /usr/bin/stap)
sdt_stap:benchmark (on %* in /usr/bin/stap)
sdt_stap:benchmark__thread__end (on %* in /usr/bin/stap)
sdt_stap:pass6__start (on %* in /usr/bin/stap)
sdt_stap:pass6__end (on %* in /usr/bin/stap)
sdt_stap:pass5__start (on %* in /usr/bin/stap)
sdt_stap:pass5__end (on %* in /usr/bin/stap)
sdt_stap:pass0__start (on %* in /usr/bin/stap)
sdt_stap:pass0__end (on %* in /usr/bin/stap)
sdt_stap:pass1a__start (on %* in /usr/bin/stap)
sdt_stap:pass1b__start (on %* in /usr/bin/stap)
sdt_stap:pass1__end (on %* in /usr/bin/stap)
sdt_stap:pass2__start (on %* in /usr/bin/stap)
sdt_stap:pass2__end (on %* in /usr/bin/stap)
sdt_stap:pass3__start (on %* in /usr/bin/stap)
sdt_stap:pass3__end (on %* in /usr/bin/stap)
sdt_stap:pass4__start (on %* in /usr/bin/stap)
sdt_stap:pass4__end (on %* in /usr/bin/stap)
sdt_stap:benchmark__start (on %* in /usr/bin/stap)
sdt_stap:benchmark__end (on %* in /usr/bin/stap)
sdt_stap:cache__get (on %* in /usr/bin/stap)
sdt_stap:cache__clean (on %* in /usr/bin/stap)
sdt_stap:cache__add__module (on %* in /usr/bin/stap)
sdt_stap:cache__add__source (on %* in /usr/bin/stap)
sdt_stap:stap_system__complete (on %* in /usr/bin/stap)
sdt_stap:stap_system__start (on %* in /usr/bin/stap)
sdt_stap:stap_system__spawn (on %* in /usr/bin/stap)
sdt_stap:stap_system__fork (on %* in /usr/bin/stap)
sdt_stap:intern_string (on %* in /usr/bin/stap)
sdt_stap:client__start (on %* in /usr/bin/stap)
sdt_stap:client__end (on %* in /usr/bin/stap)

You can now use it in all perf tools, such as:

perf record -e sdt_stap:client__end -aR sleep 1

#

From these we're use the two below to run systemtap's test suite:

# perf record -e sdt_stap:pass2__*,cycles:P make installcheck > /dev/null
^C[ perf record: Woken up 8 times to write data ]
[ perf record: Captured and wrote 2.691 MB perf.data (39638 samples) ]
Terminated
# perf script | grep sdt_stap
stap 28979 [000] 19424.302660: sdt_stap:pass2__start: (561b9a537de3) arg1=140730364262544
stap 28979 [000] 19424.333083: sdt_stap:pass2__end: (561b9a53a9e1) arg1=140730364262544
stap 29045 [006] 19424.933460: sdt_stap:pass2__start: (563edddcede3) arg1=140722674883152
stap 29045 [006] 19424.963794: sdt_stap:pass2__end: (563edddd19e1) arg1=140722674883152
# perf script | grep cycles | wc -l
39634
#

Looking at the whole perf.data file:

[root@quaco testsuite]# perf report | grep cycles:P -A25
# Samples: 39K of event 'cycles:P'
# Event count (approx.): 34044267368
#
# Overhead Command Shared Object Symbol
# ........ ....... .................... ................................
#
3.50% cc1 cc1 [.] ht_lookup_with_hash
3.04% cc1 cc1 [.] _cpp_lex_token
2.11% cc1 cc1 [.] ggc_internal_alloc
1.83% cc1 cc1 [.] cpp_get_token_with_location
1.68% cc1 libc-2.29.so [.] _int_malloc
1.41% cc1 cc1 [.] linemap_position_for_column
1.25% cc1 cc1 [.] ggc_internal_cleared_alloc
1.20% cc1 cc1 [.] c_lex_with_flags
1.18% cc1 cc1 [.] get_combined_adhoc_loc
1.05% cc1 libc-2.29.so [.] malloc
1.01% cc1 libc-2.29.so [.] _int_free
0.96% stap stap [.] std::_Hashtable<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::__detail::_Identity, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, stringtable_hash, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, true, true> >::_M_insert<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__detail::_AllocNode<std::allocator<std::__detail::_Hash_node<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, true> > > >
0.78% stap stap [.] lexer::scan
0.74% cc1 cc1 [.] _cpp_lex_direct
0.70% cc1 cc1 [.] pop_scope
0.70% cc1 cc1 [.] c_parser_declspecs
0.69% stap libc-2.29.so [.] _int_malloc
0.68% cc1 cc1 [.] htab_find_slot
0.68% cc1 [kernel.vmlinux] [k] prepare_exit_to_usermode
0.64% cc1 [kernel.vmlinux] [k] clear_page_erms
[root@quaco testsuite]#

And now only what happens in slices demarcated by those start/end SDT
events:

[root@quaco testsuite]# perf report --switch-on=sdt_stap:pass2__start --switch-off=sdt_stap:pass2__end | grep cycles:P -A100
# Samples: 240 of event 'cycles:P'
# Event count (approx.): 206491934
#
# Overhead Command Shared Object Symbol
# ........ ....... ................... ................................................
#
38.99% stap stap [.] systemtap_session::register_library_aliases
19.47% stap stap [.] match_key::operator<
15.01% stap libc-2.29.so [.] __memcmp_avx2_movbe
5.19% stap libc-2.29.so [.] _int_malloc
2.50% stap libstdc++.so.6.0.26 [.] std::_Rb_tree_insert_and_rebalance
2.30% stap stap [.] match_node::build_no_more
2.07% stap libc-2.29.so [.] malloc
1.66% stap stap [.] std::_Rb_tree<match_key, std::pair<match_key const, match_node*>, std::_Select1st<std::pair<match_key const, match_node*> >, std::less<match_key>, std::allocator<std::pair<match_key const, match_node*> > >::find
1.66% stap stap [.] match_node::bind
1.58% stap [kernel.vmlinux] [k] prepare_exit_to_usermode
1.17% stap [kernel.vmlinux] [k] native_irq_return_iret
0.87% stap stap [.] 0x0000000000032ec4
0.77% stap libstdc++.so.6.0.26 [.] std::_Rb_tree_increment
0.47% stap stap [.] std::vector<derived_probe_builder*, std::allocator<derived_probe_builder*> >::_M_realloc_insert<derived_probe_builder* const&>
0.47% stap [kernel.vmlinux] [k] get_page_from_freelist
0.47% stap [kernel.vmlinux] [k] swapgs_restore_regs_and_return_to_usermode
0.47% stap [kernel.vmlinux] [k] do_user_addr_fault
0.46% stap [kernel.vmlinux] [k] __pagevec_lru_add_fn
0.46% stap stap [.] std::_Rb_tree<match_key, std::pair<match_key const, match_node*>, std::_Select1st<std::pair<match_key const, match_node*> >, std::less<match_key>, std::allocator<std::pair<match_key const, match_node*> > >::_M_emplace_unique<std::pair<match_key, match_node*> >
0.42% stap libstdc++.so.6.0.26 [.] 0x00000000000c18fa
0.40% stap [kernel.vmlinux] [k] interrupt_entry
0.40% stap [kernel.vmlinux] [k] update_load_avg
0.40% stap [kernel.vmlinux] [k] __intel_pmu_disable_all
0.40% stap [kernel.vmlinux] [k] clear_page_erms
0.39% stap [kernel.vmlinux] [k] __mod_node_page_state
0.39% stap [kernel.vmlinux] [k] error_entry
0.39% stap [kernel.vmlinux] [k] sync_regs
0.38% stap [kernel.vmlinux] [k] __handle_mm_fault
0.38% stap stap [.] derive_probes

#
# (Tip: System-wide collection from all CPUs: perf record -a)
#
[root@quaco testsuite]#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: William Cohen <wcohen@redhat.com>
Link: https://lkml.kernel.org/n/tip-408hvumcnyn93a0auihnawew@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-report.txt | 17 +++++++++++++++++
tools/perf/builtin-report.c | 10 ++++++++++
2 files changed, 27 insertions(+)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 987261d158d4..7315f155803f 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -438,6 +438,23 @@ OPTIONS

perf report --time 0%-10%,30%-40%

+--switch-on EVENT_NAME::
+ Only consider events after this event is found.
+
+ This may be interesting to measure a workload only after some initialization
+ phase is over, i.e. insert a perf probe at that point and then using this
+ option with that probe.
+
+--switch-off EVENT_NAME::
+ Stop considering events after this event is found.
+
+--show-on-off-events::
+ Show the --switch-on/off events too. This has no effect in 'perf report' now
+ but probably we'll make the default not to show the switch-on/off events
+ on the --group mode and if there is only one event besides the off/on ones,
+ go straight to the histogram browser, just like 'perf report' with no events
+ explicitely specified does.
+
--itrace::
Options for decoding instruction tracing data. The options are:

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index d4288dcce156..5e003d02821e 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -25,6 +25,7 @@
#include "util/debug.h"
#include "util/evlist.h"
#include "util/evsel.h"
+#include "util/evswitch.h"
#include "util/header.h"
#include "util/session.h"
#include "util/tool.h"
@@ -60,6 +61,7 @@
struct report {
struct perf_tool tool;
struct perf_session *session;
+ struct evswitch evswitch;
bool use_tui, use_gtk, use_stdio;
bool show_full_info;
bool show_threads;
@@ -243,6 +245,9 @@ static int process_sample_event(struct perf_tool *tool,
return 0;
}

+ if (evswitch__discard(&rep->evswitch, evsel))
+ return 0;
+
if (machine__resolve(machine, &al, sample) < 0) {
pr_debug("problem processing %d event, skipping it.\n",
event->header.type);
@@ -1189,6 +1194,7 @@ int cmd_report(int argc, const char **argv)
OPT_CALLBACK(0, "time-quantum", &symbol_conf.time_quantum, "time (ms|us|ns|s)",
"Set time quantum for time sort key (default 100ms)",
parse_time_quantum),
+ OPTS_EVSWITCH(&report.evswitch),
OPT_END()
};
struct perf_data data = {
@@ -1257,6 +1263,10 @@ int cmd_report(int argc, const char **argv)
if (session == NULL)
return -1;

+ ret = evswitch__init(&report.evswitch, session->evlist, stderr);
+ if (ret)
+ return ret;
+
if (zstd_init(&(session->zstd_data), 0) < 0)
pr_warning("Decompression initialization failed. Reported data may be incomplete.\n");

--
2.21.0