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Subject[GIT PULL] perf tools updates
Date
Ingo,

Please pull the perf/core branch that can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git
perf/core

It adds the inverted callchains support and let one use
parent filtering with parent sorting at the same time, because
it appears to me that inverted callchains sorted by filtered
parents is pretty useful, and extendable to more cool things.

Anyway inverted callchains used with some different sorting combination
in general can provide some interesting analysis flavours.

Having played with it a bit. It seems to me the callee point
of view (traditional -g callchains) is better suited to
find the precise zoomed-in places where cpu time is most
spent. Spot contention places, etc...

OTOH, caller point of view (-G, inverted callchain), is
for zoomed out observation, of course. It's more suited for
global profiling. To get a big overview of where the hot bulk
of a program is executing for example.

Examples:

- look at the hottest tree of call of a program.

./perf report -G -s pid --stdio

5.73% perf:11933
|
--- __libc_start_main
|
|--99.18%-- main
| run_builtin
| cmd_bench
| |
| |--89.68%-- bench_sched_messaging
| | |
| | |--96.11%-- create_worker
| | | |
| | | |--95.10%-- __libc_fork
| | | | |
| | | | |--93.99%-- stub_clone
| | | | | sys_clone
| | | | | do_fork
| | | | | |
| | | | | |--99.09%-- copy_process
| | | | | | |
| | | | | | |--91.62%-- dup_mm

- look at where kernel threads spend their time

perf report -G -p kernel_thread -s parent --stdio

# Overhead Parent symbol
# ........ .............
#
0.07% kernel_thread_helper
|
--- kernel_thread_helper
kthread
|
|--50.00%-- kjournald2
| jbd2_journal_commit_transaction
| journal_submit_commit_record
| submit_bh
| submit_bio
| generic_make_request
| __make_request
| __blk_run_queue
| scsi_request_fn
| scsi_dispatch_cmd
| ata_scsi_queuecmd
| ata_scsi_translate
| ata_qc_issue
| ata_bmdma_qc_issue
| ata_sff_qc_issue
| ata_sff_tf_load
| ata_sff_check_status
| ioread8
|
--50.00%-- rcu_kthread
rcu_process_callbacks
delayed_put_task_struct
__put_task_struct
free_task
free_thread_info
free_thread_xstate
kmem_cache_free
__slab_free
add_partial
_raw_spin_lock
lock_acquire

etc...

We could extend that by applying some cut in the callchains.
For example stop a callchain on a given dso and you can profile
which exported function is most called in it.

Anyway, this has some nice potential.


Thanks,
Frederic
---

Frederic Weisbecker (5):
perf tools: Make sort operations static
perf tools: Remove sort print helpers declarations
perf tools: Don't display ignored entries on stdio ui
perf tools: Allow sort dimensions to be registered more than once
perf tools: Only display parent field if explictly sorted

Sam Liao (1):
perf tools: Add inverted call graph report support.


tools/perf/Documentation/perf-report.txt | 15 ++-
tools/perf/builtin-report.c | 42 +++++-
tools/perf/util/callchain.h | 6 +
tools/perf/util/hist.c | 6 +-
tools/perf/util/session.c | 7 +-
tools/perf/util/sort.c | 223 ++++++++++++++----------------
tools/perf/util/sort.h | 14 --
7 files changed, 169 insertions(+), 144 deletions(-)


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