Re: [PATCH v2] perf annotate/report: Remove hist__account_cycles from callback

From: Jin, Yao
Date: Fri Mar 15 2019 - 09:12:44 EST

On 3/15/2019 8:54 PM, Jiri Olsa wrote:
On Fri, Mar 15, 2019 at 09:46:01PM +0800, Jin Yao wrote:
The hist__account_cycles is executed when the hist_iter__branch_callback
is called. But it looks it's not necessary. In hist__account_cycles, it
already walks on all branch entries.

This patch moves the hist__account_cycles out of callback, now the data
processing is much faster than before.

Previous code has an issue that the ch[offset].num++
(in __symbol__account_cycles) is executed repeatedly since
hist__account_cycles is called in each hist_iter__branch_callback,
so the counting of ch[offset].num is not correct (too big).
With this patch, the issue is fixed. And we don't need the code of
"ch->reset >= ch->num / 2" to check if there are too many overlaps
(in annotation__count_and_fill), otherwise some data would be

Now, we can try, for example:

perf record -b ...
perf annotate or perf report -s symbol

im getting crash in stdio mode:

[root@krava perf]# ./perf record -b ./perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes

Total time: 21.384 [sec]

21.384381 usecs/op
46763 ops/sec
[ perf record: Woken up 464 times to write data ]
[ perf record: Captured and wrote 116.873 MB (150149 samples) ]
[root@krava perf]# ./perf report
File not owned by current user or root (use -f to override)
[root@krava perf]# ./perf report -f
[root@krava perf]# ./perf report -f --stdio
Segmentation fault (core dumped)

(gdb) r report -f --stdio
Starting program: /home/jolsa/kernel/linux-perf/tools/perf/perf report -f --stdio
Missing separate debuginfos, use: dnf debuginfo-install glibc-2.27-37.fc28.x86_64
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/".
warning: Loadable section "" outside of ELF segments
Detaching after fork from child process 706.

Program received signal SIGSEGV, Segmentation fault.
symbol__cycles_hist (sym=0xcfb730) at util/annotate.c:892
892 if (!notes->src->cycles_hist) {
Missing separate debuginfos, use: dnf debuginfo-install bzip2-libs-1.0.6-26.fc28.x86_64 elfutils-libelf-0.174-5.fc28.x86_64 elfutils-libs-0.174-5.fc28.x86_64 libgcc-8.3.1-2.fc28.x86_64 libunwind-1.2.1-5.fc28.x86_64 libxcrypt-4.4.4-1.fc28.x86_64 numactl-libs-2.0.11-8.fc28.x86_64 openssl-libs-1.1.0i-1.fc28.x86_64 perl-libs-5.26.3-416.fc28.x86_64 python2-libs-2.7.15-4.fc28.x86_64 slang-2.3.2-2.fc28.x86_64 xz-libs-5.2.4-2.fc28.x86_64 zlib-1.2.11-8.fc28.x86_64
(gdb) bt
#0 symbol__cycles_hist (sym=0xcfb730) at util/annotate.c:892
#1 0x00000000004d91e8 in symbol__account_cycles (addr=140735827492712, start=140735827492708, sym=0xcfb730, cycles=2) at util/annotate.c:942
#2 0x00000000004d9403 in addr_map_symbol__account_cycles (ams=0xd629d8, start=0xd62a68, cycles=2) at util/annotate.c:989
#3 0x000000000056fccd in hist__account_cycles (bs=0x7fffed05f230, al=0x7fffffffaac0, sample=0x7fffffffac50, nonany_branch_mode=false) at util/hist.c:2527
#4 0x0000000000448f6d in process_sample_event (tool=0x7fffffffb7d0, event=0x7fffed05f208, sample=0x7fffffffac50, evsel=0xccc920, machine=0xcc5ee0) at builtin-report.c:279
#5 0x000000000053e7dd in perf_evlist__deliver_sample (evlist=0xcc5030, tool=0x7fffffffb7d0, event=0x7fffed05f208, sample=0x7fffffffac50, evsel=0xccc920, machine=0xcc5ee0) at util/session.c:1251
#6 0x000000000053e971 in machines__deliver_event (machines=0xcc5ee0, evlist=0xcc5030, event=0x7fffed05f208, sample=0x7fffffffac50, tool=0x7fffffffb7d0, file_offset=29192) at util/session.c:1288
#7 0x000000000053edc3 in perf_session__deliver_event (session=0xcc5de0, event=0x7fffed05f208, tool=0x7fffffffb7d0, file_offset=29192) at util/session.c:1361
#8 0x000000000053b772 in ordered_events__deliver_event (oe=0xccc878, event=0xceae60) at util/session.c:116
#9 0x0000000000543030 in do_flush (oe=0xccc878, show_progress=false) at util/ordered-events.c:243
#10 0x000000000054335f in __ordered_events__flush (oe=0xccc878, how=OE_FLUSH__ROUND, timestamp=0) at util/ordered-events.c:320
#11 0x0000000000543434 in ordered_events__flush (oe=0xccc878, how=OE_FLUSH__ROUND) at util/ordered-events.c:338
#12 0x000000000053d7dd in process_finished_round (tool=0x7fffffffb7d0, event=0x7fffed106358, oe=0xccc878) at util/session.c:871
#13 0x000000000053eff3 in perf_session__process_user_event (session=0xcc5de0, event=0x7fffed106358, file_offset=713560) at util/session.c:1401
#14 0x000000000053f67e in perf_session__process_event (session=0xcc5de0, event=0x7fffed106358, file_offset=713560) at util/session.c:1528
#15 0x000000000054066d in process_simple (session=0xcc5de0, event=0x7fffed106358, file_offset=713560) at util/session.c:1961
#16 0x00000000005404d5 in reader__process_events (rd=0x7fffffffb560, session=0xcc5de0, prog=0x7fffffffb580) at util/session.c:1931
#17 0x0000000000540759 in __perf_session__process_events (session=0xcc5de0) at util/session.c:1984
#18 0x000000000054088a in perf_session__process_events (session=0xcc5de0) at util/session.c:2017
#19 0x000000000044a984 in __cmd_report (rep=0x7fffffffb7d0) at builtin-report.c:852
#20 0x000000000044cc24 in cmd_report (argc=0, argv=0x7fffffffd960) at builtin-report.c:1440
#21 0x00000000004d408b in run_builtin (p=0xb47d30 <commands+240>, argc=3, argv=0x7fffffffd960) at perf.c:302
#22 0x00000000004d42f8 in handle_internal_command (argc=3, argv=0x7fffffffd960) at perf.c:354
#23 0x00000000004d4447 in run_argv (argcp=0x7fffffffd7bc, argv=0x7fffffffd7b0) at perf.c:398
#24 0x00000000004d47b3 in main (argc=3, argv=0x7fffffffd960) at perf.c:520


Oh, like previous code, it needs the checking of ui__has_annotation() before hist__account_cycles(), but I forgot to add this. :(

My mistake, sorry about that.

Jin Yao