Hello,
This work is to make the output compact by removing dummy events in
the output. The dummy events are used to save side-band information
like task creation or memory address space change using mmap(2). But
after collecting these, it's not used because it won't have any
samples.
v2 changes)
* just hide the (dummy) event instead of removing it from evlist
v3 changes)
* rename to struct hpp_fmt_value (Arnaldo)
* add Tested-by from Arnaldo
Sometimes users want to run perf report --group to show all recorded
events together but they are not interested in those dummy events.
This just wastes the precious screen space so we want to get rid of
them in the output.
perf report already has --skip-empty option to skip 0 result in the
stat output. I think we can extend it to skip empty events that have
no samples.
Example output:
$ sudo perf mem record -a sleep 1
$ sudo perf report --group
Before)
#
# Samples: 232 of events 'cpu/mem-loads,ldlat=30/P, cpu/mem-stores/P, dummy:u'
# Event count (approx.): 3089861
#
# Overhead Command Shared Object Symbol
# ........................ ........... ................. .....................................
#
9.29% 0.00% 0.00% swapper [kernel.kallsyms] [k] update_blocked_averages
5.26% 0.15% 0.00% swapper [kernel.kallsyms] [k] __update_load_avg_se
4.15% 0.00% 0.00% perf-exec [kernel.kallsyms] [k] slab_update_freelist.isra.0
3.87% 0.00% 0.00% perf-exec [kernel.kallsyms] [k] memcg_slab_post_alloc_hook
3.79% 0.17% 0.00% swapper [kernel.kallsyms] [k] enqueue_task_fair
3.63% 0.00% 0.00% sleep [kernel.kallsyms] [k] next_uptodate_page
2.86% 0.00% 0.00% swapper [kernel.kallsyms] [k] __update_load_avg_cfs_rq
2.78% 0.00% 0.00% swapper [kernel.kallsyms] [k] __schedule
2.34% 0.00% 0.00% swapper [kernel.kallsyms] [k] intel_idle
2.32% 0.97% 0.00% swapper [kernel.kallsyms] [k] psi_group_change
After)
#
# Samples: 232 of events 'cpu/mem-loads,ldlat=30/P, cpu/mem-stores/P'
# Event count (approx.): 3089861
#
# Overhead Command Shared Object Symbol
# ................ ........... ................. .....................................
#
9.29% 0.00% swapper [kernel.kallsyms] [k] update_blocked_averages
5.26% 0.15% swapper [kernel.kallsyms] [k] __update_load_avg_se
4.15% 0.00% perf-exec [kernel.kallsyms] [k] slab_update_freelist.isra.0
3.87% 0.00% perf-exec [kernel.kallsyms] [k] memcg_slab_post_alloc_hook
3.79% 0.17% swapper [kernel.kallsyms] [k] enqueue_task_fair
3.63% 0.00% sleep [kernel.kallsyms] [k] next_uptodate_page
2.86% 0.00% swapper [kernel.kallsyms] [k] __update_load_avg_cfs_rq
2.78% 0.00% swapper [kernel.kallsyms] [k] __schedule
2.34% 0.00% swapper [kernel.kallsyms] [k] intel_idle
2.32% 0.97% swapper [kernel.kallsyms] [k] psi_group_change
Now 'Overhead' column only has two values for mem-loads and mem-stores.
Thanks,
Namhyung
Namhyung Kim (4):
perf hist: Factor out __hpp__fmt_print()
perf hist: Simplify __hpp_fmt() using hpp_fmt_data
perf hist: Add symbol_conf.skip_empty
perf hist: Honor symbol_conf.skip_empty
tools/perf/builtin-annotate.c | 4 +-
tools/perf/builtin-report.c | 12 +--
tools/perf/ui/hist.c | 144 ++++++++++++++++-----------------
tools/perf/ui/stdio/hist.c | 5 +-
tools/perf/util/events_stats.h | 3 +-
tools/perf/util/evsel.c | 13 ++-
tools/perf/util/hist.c | 6 +-
tools/perf/util/hist.h | 3 +-
tools/perf/util/python.c | 3 +
tools/perf/util/session.c | 5 +-
tools/perf/util/session.h | 3 +-
tools/perf/util/symbol_conf.h | 3 +-
12 files changed, 105 insertions(+), 99 deletions(-)
--
2.45.2.505.gda0bf45e8d-goog