Re: [PATCH 19/19] perf stat: Remove unused perf_counts.aggr field

From: Jiri Olsa
Date: Wed Oct 12 2022 - 04:41:15 EST

On Sun, Oct 09, 2022 at 10:36:00PM -0700, Namhyung Kim wrote:
> The aggr field in the struct perf_counts is to keep the aggregated value
> in the AGGR_GLOBAL for the old code. But it's not used anymore.
>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
> tools/perf/util/counts.c | 1 -
> tools/perf/util/counts.h | 1 -
> tools/perf/util/stat.c | 35 ++---------------------------------
> 3 files changed, 2 insertions(+), 35 deletions(-)
>
> diff --git a/tools/perf/util/counts.c b/tools/perf/util/counts.c
> index 7a447d918458..11cd85b278a6 100644
> --- a/tools/perf/util/counts.c
> +++ b/tools/perf/util/counts.c
> @@ -48,7 +48,6 @@ void perf_counts__reset(struct perf_counts *counts)
> {
> xyarray__reset(counts->loaded);
> xyarray__reset(counts->values);
> - memset(&counts->aggr, 0, sizeof(struct perf_counts_values));
> }
>
> void evsel__reset_counts(struct evsel *evsel)
> diff --git a/tools/perf/util/counts.h b/tools/perf/util/counts.h
> index 5de275194f2b..42760242e0df 100644
> --- a/tools/perf/util/counts.h
> +++ b/tools/perf/util/counts.h
> @@ -11,7 +11,6 @@ struct evsel;
>
> struct perf_counts {
> s8 scaled;
> - struct perf_counts_values aggr;
> struct xyarray *values;
> struct xyarray *loaded;
> };
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 1652586a4925..0dccfa273fa7 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -307,8 +307,6 @@ static void evsel__copy_prev_raw_counts(struct evsel *evsel)
> *perf_counts(evsel->prev_raw_counts, idx, thread);
> }
> }
> -
> - evsel->counts->aggr = evsel->prev_raw_counts->aggr;
> }
>
> void evlist__copy_prev_raw_counts(struct evlist *evlist)
> @@ -319,26 +317,6 @@ void evlist__copy_prev_raw_counts(struct evlist *evlist)
> evsel__copy_prev_raw_counts(evsel);
> }
>
> -void evlist__save_aggr_prev_raw_counts(struct evlist *evlist)
> -{
> - struct evsel *evsel;
> -
> - /*
> - * To collect the overall statistics for interval mode,
> - * we copy the counts from evsel->prev_raw_counts to
> - * evsel->counts. The perf_stat_process_counter creates
> - * aggr values from per cpu values, but the per cpu values
> - * are 0 for AGGR_GLOBAL. So we use a trick that saves the
> - * previous aggr value to the first member of perf_counts,
> - * then aggr calculation in process_counter_values can work
> - * correctly.
> - */
> - evlist__for_each_entry(evlist, evsel) {
> - *perf_counts(evsel->prev_raw_counts, 0, 0) =
> - evsel->prev_raw_counts->aggr;
> - }
> -}
> -
> static size_t pkg_id_hash(const void *__key, void *ctx __maybe_unused)
> {
> uint64_t *key = (uint64_t *) __key;
> @@ -422,7 +400,6 @@ process_counter_values(struct perf_stat_config *config, struct evsel *evsel,
> int cpu_map_idx, int thread,
> struct perf_counts_values *count)
> {
> - struct perf_counts_values *aggr = &evsel->counts->aggr;
> struct perf_stat_evsel *ps = evsel->stats;
> static struct perf_counts_values zero;
> bool skip = false;
> @@ -491,12 +468,6 @@ process_counter_values(struct perf_stat_config *config, struct evsel *evsel,
> }
> }
>
> - if (config->aggr_mode == AGGR_GLOBAL) {
> - aggr->val += count->val;
> - aggr->ena += count->ena;
> - aggr->run += count->run;
> - }
> -
> return 0;
> }
>
> @@ -521,13 +492,10 @@ static int process_counter_maps(struct perf_stat_config *config,
> int perf_stat_process_counter(struct perf_stat_config *config,
> struct evsel *counter)
> {
> - struct perf_counts_values *aggr = &counter->counts->aggr;
> struct perf_stat_evsel *ps = counter->stats;
> - u64 *count = counter->counts->aggr.values;
> + u64 *count;
> int ret;
>
> - aggr->val = aggr->ena = aggr->run = 0;
> -
> if (counter->per_pkg)
> evsel__zero_per_pkg(counter);
>
> @@ -538,6 +506,7 @@ int perf_stat_process_counter(struct perf_stat_config *config,
> if (config->aggr_mode != AGGR_GLOBAL)
> return 0;
>
> + count = ps->aggr[0].counts.values;
> update_stats(&ps->res_stats, *count);

hi,
for some reason 'count' could be NULL, I'm getting crash in here:

$ ./perf stat record -o krava.data true
...

$ gdb ./perf

(gdb) r stat report -i krava.data
Starting program: /home/jolsa/kernel/linux-perf/tools/perf/perf stat report -i krava.data
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00000000005ae90b in perf_stat_process_counter (config=0xe18d60 <stat_config>, counter=0xecfd00) at util/stat.c:510
510 update_stats(&ps->res_stats, *count);
Missing separate debuginfos, use: dnf debuginfo-install bzip2-libs-1.0.8-11.fc36.x86_64 cyrus-sasl-lib-2.1.27-18.fc36.x86_64 elfutils-debuginfod-client-0.187-4.fc36.x86_64 elfutils-libelf-0.187-4.fc36.x86_64 elfutils-libs-0.187-4.fc36.x86_64 glibc-2.35-15.fc36.x86_64 glibc-2.35-17.fc36.x86_64 keyutils-libs-1.6.1-4.fc36.x86_64 krb5-libs-1.19.2-11.fc36.x86_64 libbrotli-1.0.9-7.fc36.x86_64 libcap-2.48-4.fc36.x86_64 libcom_err-1.46.5-2.fc36.x86_64 libcurl-7.82.0-8.fc36.x86_64 libevent-2.1.12-6.fc36.x86_64 libgcc-12.2.1-2.fc36.x86_64 libidn2-2.3.3-1.fc36.x86_64 libnghttp2-1.46.0-2.fc36.x86_64 libpsl-0.21.1-5.fc36.x86_64 libselinux-3.3-4.fc36.x86_64 libssh-0.9.6-4.fc36.x86_64 libunistring-1.0-1.fc36.x86_64 libunwind-1.6.2-2.fc36.x86_64 libxcrypt-4.4.28-1.fc36.x86_64 libzstd-1.5.2-2.fc36.x86_64 numactl-libs-2.0.14-5.fc36.x86_64 openldap-2.6.3-1.fc36.x86_64 openssl-libs-3.0.5-1.fc36.x86_64 perl-libs-5.34.1-486.fc36.x86_64 python3-libs-3.10.7-1.fc36.x86_64 slang-2.3.2-11.fc36.x86_64 xz-libs-5.2.5-9.fc36.x86_64 zlib-1.2.11-33.fc36.x86_64
(gdb) bt
#0 0x00000000005ae90b in perf_stat_process_counter (config=0xe18d60 <stat_config>, counter=0xecfd00) at util/stat.c:510
#1 0x000000000043b716 in process_counters () at builtin-stat.c:485
#2 0x000000000043f2bf in process_stat_round_event (session=0xec84f0, event=0x7ffff7ffaba8) at builtin-stat.c:2099
#3 0x000000000056c7b6 in perf_session__process_user_event (session=0xec84f0, event=0x7ffff7ffaba8, file_offset=2984, file_path=0xecf220 "krava.data")
at util/session.c:1714
#4 0x000000000056cea5 in perf_session__process_event (session=0xec84f0, event=0x7ffff7ffaba8, file_offset=2984, file_path=0xecf220 "krava.data")
at util/session.c:1857
#5 0x000000000056e4fa in process_simple (session=0xec84f0, event=0x7ffff7ffaba8, file_offset=2984, file_path=0xecf220 "krava.data") at util/session.c:2432
#6 0x000000000056e1b9 in reader__read_event (rd=0x7fffffffb6c0, session=0xec84f0, prog=0x7fffffffb690) at util/session.c:2361
#7 0x000000000056e3ae in reader__process_events (rd=0x7fffffffb6c0, session=0xec84f0, prog=0x7fffffffb690) at util/session.c:2410
#8 0x000000000056e652 in __perf_session__process_events (session=0xec84f0) at util/session.c:2457
#9 0x000000000056eff8 in perf_session__process_events (session=0xec84f0) at util/session.c:2623
#10 0x000000000043fa53 in __cmd_report (argc=0, argv=0x7fffffffdf70) at builtin-stat.c:2265
#11 0x000000000043fd94 in cmd_stat (argc=3, argv=0x7fffffffdf70) at builtin-stat.c:2346
#12 0x00000000004ef495 in run_builtin (p=0xe2f930 <commands+336>, argc=4, argv=0x7fffffffdf70) at perf.c:322
#13 0x00000000004ef709 in handle_internal_command (argc=4, argv=0x7fffffffdf70) at perf.c:376
#14 0x00000000004ef858 in run_argv (argcp=0x7fffffffdd9c, argv=0x7fffffffdd90) at perf.c:420
#15 0x00000000004efc1f in main (argc=4, argv=0x7fffffffdf70) at perf.c:550
(gdb) p count
$1 = (u64 *) 0x0

jirka

>
> if (verbose > 0) {
> --
> 2.38.0.rc1.362.ged0d419d3c-goog
>