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    SubjectRe: [GIT PULL 00/11] perf/core improvements and fixes

    * Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

    > Hi Ingo,
    >
    > Please consider pulling,
    >
    > - Arnaldo
    >
    > The following changes since commit 675965b00d734c985e4285f5bec7e524d15fc4e1:
    >
    > perf: Export perf_event_sysfs_show() (2016-02-29 09:35:27 +0100)
    >
    > are available in the git repository at:
    >
    > git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-core-for-mingo-20160229
    >
    > for you to fetch changes up to 575a02e00b11eecbbabcb1eb22eab4c68e91ae77:
    >
    > perf record: Ensure return non-zero rc when mmap fail (2016-02-29 12:44:15 -0300)
    >
    > ----------------------------------------------------------------
    > perf/core improvements and fixes:
    >
    > User visible:
    >
    > - Check existence of frontend/backed stalled cycles in 'perf stat' (Andi Kleen)
    >
    > - Avoid installing .o files from tools/lib/ into the python extension (Jiri Olsa)
    >
    > - Rename the tracepoint '/format' field that carries the syscall ID from 'nr',
    > that is also the name of some syscalls arguments, to "__syscall_nr", to
    > avoid having multiple fields with the same name, that was breaking the
    > python script skeleton generator from perf.data files (Taeung Song)
    >
    > - Support converting data from bpf events in 'perf data' (Wang Nan)
    >
    > Infrastructure:
    >
    > - Split libtraceevent's pevent_print_event() (Steven Rostedt)
    >
    > - Librarize some 'perf record' bits to allow handling multiple perf.data
    > files per session (Wang Nan)
    >
    > - Ensure return non-zero rc when mmap fail in 'perf record' (Wang Nan)
    >
    > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    >
    > ----------------------------------------------------------------
    > Andi Kleen (1):
    > perf stat: Check existence of frontend/backed stalled cycles

    >
    > Jiri Olsa (1):
    > perf tools: Fix python extension build
    >
    > Steven Rostedt (1):
    > tools lib traceevent: Split pevent_print_event() into specific functionality functions
    >
    > Taeung Song (2):
    > perf trace: Check and discard not only 'nr' but also '__syscall_nr'
    > tracing/syscalls: Rename "/format" tracepoint field name "nr" to "__syscall_nr:
    >
    > Wang Nan (6):
    > perf data: Support converting data from bpf_perf_event_output()
    > perf data: Explicitly set byte order for integer types
    > perf record: Use WARN_ONCE to replace 'if' condition
    > perf record: Extract synthesize code to record__synthesize()
    > perf record: Introduce record__finish_output() to finish a perf.data
    > perf record: Ensure return non-zero rc when mmap fail
    >
    > kernel/trace/trace_syscalls.c | 16 ++--
    > tools/lib/traceevent/event-parse.c | 136 +++++++++++++++++++++++-------
    > tools/lib/traceevent/event-parse.h | 13 +++
    > tools/perf/builtin-record.c | 168 ++++++++++++++++++++++---------------
    > tools/perf/builtin-stat.c | 22 ++++-
    > tools/perf/builtin-trace.c | 8 +-
    > tools/perf/util/data-convert-bt.c | 118 +++++++++++++++++++++++++-
    > tools/perf/util/setup.py | 4 +
    > 8 files changed, 372 insertions(+), 113 deletions(-)

    Hm, there's a 'perf stat' regression that I can see:

    Before:

    triton:~/tip> perf stat -a sleep 1

    Performance counter stats for 'system wide':

    11990.023100 task-clock (msec) # 11.981 CPUs utilized
    8,802 context-switches # 0.734 K/sec
    543 cpu-migrations # 0.045 K/sec
    97,375 page-faults # 0.008 M/sec
    9,854,385,894 cycles # 0.822 GHz
    15,274,841,152 stalled-cycles-frontend # 155.01% frontend cycles idle
    <not supported> stalled-cycles-backend
    9,634,486,137 instructions # 0.98 insn per cycle
    # 1.59 stalled cycles per insn
    1,818,488,088 branches # 151.667 M/sec
    46,365,120 branch-misses # 2.55% of all branches

    1.000741599 seconds time elapsed

    After:

    triton:~/tip> perf stat -a sleep 1

    Performance counter stats for 'system wide':

    11989.280397 task-clock (msec) # 11.981 CPUs utilized
    1299 context-switches # 0.108 K/sec
    6 cpu-migrations # 0.001 K/sec
    70 page-faults # 0.006 K/sec
    127008602 cycles # 0.011 GHz
    279538533 stalled-cycles-frontend # 220.09% frontend cycles idle
    119213269 instructions # 0.94 insn per cycle
    # 2.34 stalled cycles per insn
    24166678 branches # 2.016 M/sec
    505681 branch-misses # 2.09% of all branches

    1.000684278 seconds time elapsed


    ... see how the numbers became human-unreadable, losing the big-number separator?

    I suspect it's due to the following commit:

    fa184776ac27 perf stat: Check existence of frontend/backed stalled cycles

    Thanks,

    Ingo

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