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Date: Tue, 17 Dec 2019 09:47:01 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: Jiri Olsa <jolsa@...hat.com>
Cc: acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com,
Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v3 1/3] perf report: Change sort order by a specified
event in group
On 12/16/2019 3:31 PM, Jiri Olsa wrote:
> On Thu, Dec 12, 2019 at 08:33:35PM +0800, Jin Yao wrote:
>
> SNIP
>
>>
>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>> ---
>> tools/perf/Documentation/perf-report.txt | 4 +
>> tools/perf/builtin-report.c | 10 +++
>> tools/perf/ui/hist.c | 108 +++++++++++++++++++----
>> tools/perf/util/symbol_conf.h | 1 +
>> 4 files changed, 108 insertions(+), 15 deletions(-)
>>
>> diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
>> index 8dbe2119686a..9ade613ef020 100644
>> --- a/tools/perf/Documentation/perf-report.txt
>> +++ b/tools/perf/Documentation/perf-report.txt
>> @@ -371,6 +371,10 @@ OPTIONS
>> Show event group information together. It forces group output also
>> if there are no groups defined in data file.
>>
>> +--group-sort-idx::
>> + Sort the output by the event at the index n in group. If n is invalid,
>> + sort by the first event. WARNING: This should be used with --group.
>
> --group in record or report?
>
This --group is in perf-report. So even if it's not created with -e '{}'
in perf-record, it still supports to show event information together.
> you can also create groups with -e '{}', not just --group option
>
> I wonder you could check early on 'evlist->nr_groups' and fail
> if there's no group defined if the option is enabled
>
Maybe we don't need to check that because it supports the case of no
group defined.
For example,
perf record -e cycles,instructions
perf report --group --group-sort-idx 1 --stdio
# Overhead Command Shared Object Symbol
# ................ ....... .................
.............................
#
0.00% 39.68% swapper [kernel.kallsyms] [k] file_free_rcu
0.00% 31.85% swapper [kernel.kallsyms] [k] ___perf_sw_event
3.96% 4.68% swapper [kernel.kallsyms] [k]
tick_nohz_idle_stop_tick
0.00% 4.49% perf [kernel.kallsyms] [k] update_load_avg
0.00% 4.49% swapper [kernel.kallsyms] [k] tcp_ack
4.06% 3.75% swapper [kernel.kallsyms] [k] update_rt_rq_load_avg
3.54% 3.71% swapper [kernel.kallsyms] [k] update_blocked_averages
1.88% 2.06% swapper [kernel.kallsyms] [k] load_balance
The output is sorted by the second event.
> also what happens when we have more groups?
>
Let me take an example.
perf record -e '{cycles,instructions}' -e '{branches,cache-misses}' -a
perf report --group --group-sort-idx 1 --stdio
# Samples: 116 of events 'anon group { cycles, instructions }'
# Event count (approx.): 17552917
#
# Overhead Command Shared Object Symbol
# ................ ............... .................
...............................
#
0.00% 13.81% perf [kernel.kallsyms] [k] number
0.00% 12.50% swapper [kernel.kallsyms] [k] cpuidle_select
0.00% 12.02% sleep [kernel.kallsyms] [k]
filemap_map_pages
0.00% 11.40% perf [kernel.kallsyms] [k] rcu_all_qs
0.00% 11.30% perf [kernel.kallsyms] [k] alloc_set_pte
0.00% 10.54% swapper [kernel.kallsyms] [k]
timekeeping_advance
0.00% 9.89% kworker/5:2-mm_ [kernel.kallsyms] [k]
update_rt_rq_load_avg
0.00% 7.86% rcu_sched [kernel.kallsyms] [k]
finish_task_switch
......
# Samples: 100 of events 'anon group { branches, cache-misses }'
# Event count (approx.): 1214391
#
# Overhead Command Shared Object Symbol
# ................ ............... .......................
...............................
#
0.00% 23.13% perf [kernel.kallsyms] [k]
ext4_dirty_inode
0.00% 18.66% sleep [kernel.kallsyms] [k]
free_pipe_info
0.00% 10.74% perf [kernel.kallsyms] [k]
unmap_page_range
0.00% 9.35% sleep [kernel.kallsyms] [k]
__wake_up_common_lock
0.00% 7.71% wpa_supplicant libc-2.27.so [.]
cfree@...BC_2.2.5
0.00% 6.55% thermald libglib-2.0.so.0.5600.4 [.]
g_mutex_lock
0.00% 3.43% perf [kernel.kallsyms] [k]
_raw_spin_lock
0.00% 3.12% migration/0 [kernel.kallsyms] [k]
kthread_should_stop
0.00% 2.87% migration/1 [kernel.kallsyms] [k]
__bitmap_and
0.00% 2.37% migration/3 [kernel.kallsyms] [k]
update_rt_rq_load_avg
0.00% 2.01% perf [kernel.kallsyms] [k]
security_inode_permission
0.00% 1.91% migration/5 [kernel.kallsyms] [k]
update_sd_lb_stats
0.00% 1.86% perf [kernel.kallsyms] [k]
__alloc_file
0.00% 1.83% swapper [kernel.kallsyms] [k]
intel_idle
0.00% 1.49% migration/2 [kernel.kallsyms] [k]
__switch_to_asm
0.00% 1.41% migration/6 [kernel.kallsyms] [k]
__bitmap_and
......
The outputs are sorted by the second event.
Let me take one more example of multiple groups with different amount of
events.
perf record -e '{cycles,instructions}' -e
'{branches,cache-misses,cache-references}' -a
perf report --group --group-sort-idx 2 --stdio
# Samples: 135 of events 'anon group { cycles, instructions }'
# Event count (approx.): 20558030
#
# Overhead Command Shared Object Symbol
# ................ ............... ........................
...................................
#
21.52% 0.00% perf [kernel.kallsyms] [k]
anon_vma_interval_tree_remove
10.63% 0.00% perf [kernel.kallsyms] [k] strncpy
9.61% 0.00% migration/5 [kernel.kallsyms] [k]
put_prev_task_stop
8.64% 0.00% migration/3 [kernel.kallsyms] [k]
update_blocked_averages
6.53% 0.00% migration/2 [kernel.kallsyms] [k]
update_sd_lb_stats
5.41% 0.00% migration/0 [kernel.kallsyms] [k] rb_erase
5.32% 0.00% migration/4 [kernel.kallsyms] [k]
reweight_entity
4.90% 0.00% swapper [kernel.kallsyms] [k]
e1000_clean_rx_irq
4.35% 0.00% migration/1 [kernel.kallsyms] [k] schedule
3.94% 0.00% migration/6 [kernel.kallsyms] [k]
propagate_entity_cfs_rq.isra.97
......
The output for group '{cycles, instructions}' is sorted by default
(first event) since the group-sort-idx (2) is invalid.
# Samples: 187 of events 'anon group { branches, cache-misses,
cache-references }'
# Event count (approx.): 2428023
#
# Overhead Command Shared Object
Symbol
# ........................ ............... ........................
.........................................
#
0.00% 0.00% 21.54% perf [kernel.kallsyms]
[k] up_write
0.00% 0.00% 10.01% swapper [kernel.kallsyms]
[k] note_gp_changes
0.00% 0.00% 9.51% kworker/u16:1-e [kernel.kallsyms]
[k] finish_task_switch
0.00% 12.48% 8.06% swapper [kernel.kallsyms]
[k] intel_idle
0.00% 0.00% 4.08% perf [kernel.kallsyms]
[k] kmem_cache_alloc
0.00% 0.00% 3.83% migration/3 [kernel.kallsyms]
[k] update_blocked_averages
0.00% 0.00% 3.58% migration/5 [kernel.kallsyms]
[k] pick_next_task_rt
0.00% 0.00% 3.46% swapper [kernel.kallsyms]
[k] rcu_dynticks_eqs_exit
0.00% 0.00% 3.22% swapper [kernel.kallsyms]
[k] calc_global_load
0.00% 0.00% 3.13% swapper [kernel.kallsyms]
[k] cpuidle_not_available
......
The output for group '{branches, cache-misses, cache-references}' is
sorted by the third event. It's expected.
> I think the option is easy to use as it is, just needs to be explained
> consequences for more groups with different amount of events
>
Thanks. Can we say something as following?
--group-sort-idx::
Sort the output by the event at the index n in group. If n is invalid,
sort by the first event. It can support multiple groups with different
amount of events. WARNING: This should be used with perf report --group.
> SNIP
>
>> +
>> +static int __hpp__group_sort_idx(struct hist_entry *a, struct hist_entry *b,
>> + hpp_field_fn get_field, int idx)
>> +{
>> + struct evsel *evsel = hists_to_evsel(a->hists);
>> + u64 *fields_a, *fields_b;
>> + int cmp, nr_members, ret, i;
>> +
>> + cmp = field_cmp(get_field(a), get_field(b));
>> + if (!perf_evsel__is_group_event(evsel))
>> + return cmp;
>> +
>> + nr_members = evsel->core.nr_members;
>> + ret = pair_fields_alloc(a, b, get_field, nr_members,
>> + &fields_a, &fields_b);
>> + if (ret) {
>> + ret = cmp;
>> + goto out;
>> + }
>> +
>> + if (idx >= 1 && idx < nr_members) {
>
> do we need to continue here if idx is out of the limit?
> I'm not sure but mybe in that case the comparison above
> should be enough?
>
Yes, we can use simpler code. Something like,
+ cmp = field_cmp(get_field(a), get_field(b));
+ if (!perf_evsel__is_group_event(evsel))
+ return cmp;
+
+ nr_members = evsel->core.nr_members;
+ if (idx < 1 || idx >= nr_members)
+ return cmp;
......
Thanks
Jin Yao
> thanks,
> jirka
>
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