[GIT PULL] tracing/tools: Updates for 6.15

[Steven Rostedt]

Costa Shulyupin <costa.shul@xxxxxxxxxx>, John Kacur <jkacur@xxxxxxxxxx>, Tomas Glozar <tglozar@xxxxxxxxxx>

Linus,

tracing tooling updates for 6.15:

- Allow RTLA to collect data via BPF

  The current implementation of rtla uses libtracefs and libtraceevent to
  pull sample events generated by the timerlat tracer from the trace
  buffer. rtla then processes the sample by updating the histogram and
  summary (current, maximum, minimum, and sum values) as well as checks
  if tracing has been stopped due to threshold overflow.

  In use cases where a large number of samples is being generated, that
  is, with measurements running on many CPUs and with a low interval,
  this sample processing design causes a significant CPU load on the rtla
  side. Furthermore, with >100 CPUs and 100us interval, rtla was reported
  as not being able to keep up with the samples and dropping most of them,
  leading to it being unusable.

  Change the way the timerlat trace processes samples by attaching
  a BPF program to the trace event using the BPF skeleton feature of bpftool.
  Unlike the current implementation, the BPF implementation does not check
  whether tracing is stopped (in BPF mode, tracing is always off to improve
  performance), but waits for a write to a BPF ringbuffer instead. This allows
  rtla to exit immediately when a threshold is violated, without waiting
  for the next iteration of the while loop.

  If the requirements for the BPF implementation are not met, either at
  build time or at run time, the current implementation is used as
  fallback. Which implementation is being used can be seen when running
  rtla timerlat with "-D" option. rtla can be forced to run in non-BPF
  mode by setting the RTLA_NO_BPF option to 1, for debugging purposes.

- Fix LD_FLAGS from being dropped in build

- Refactor code to remove duplication of save_trace_to_file

- Always set options and do not rely on default settings

  Do not rely on the default kernel settings of the tracers when
  starting. They could have been changed by the user which gives
  inconsistent results. Always set the options that rtla expects.

- Add creation of ctags and TAGS for traversing code


Please pull the latest trace-tools-v6.15 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace-tools-v6.15

Tag SHA1: cab13e49ba8fc5d0e9545cd41e34e59dabbd3954
Head SHA1: 732032692f6ae311bc35159b18e5b7c5e64010fc


Costa Shulyupin (1):
      rtla: Refactor save_trace_to_file

John Kacur (1):
      rtla: Add the ability to create ctags and etags

Tomas Glozar (17):
      rtla/timerlat: Unify params struct
      tools/build: Add bpftool-skeletons feature test
      rtla: Add optional dependency on BPF tooling
      rtla/timerlat: Add BPF skeleton to collect samples
      rtla/timerlat_hist: Use BPF to collect samples
      rtla/timerlat_top: Move divisor to update
      rtla/timerlat_top: Use BPF to collect samples
      rtla/timerlat: Test BPF mode
      tools/rv: Keep user LDFLAGS in build
      tools/build: Use SYSTEM_BPFTOOL for system bpftool
      rtla: Fix segfault in save_trace_to_file call
      rtla/osnoise: Unify params struct
      rtla: Unify apply_config between top and hist
      rtla/osnoise: Set OSNOISE_WORKLOAD to true
      rtla: Always set all tracer options
      rtla/tests: Reset osnoise options before check
      rtla/tests: Test setting default options

----
 tools/build/Makefile.feature           |   3 +-
 tools/build/feature/Makefile           |   3 +
 tools/scripts/Makefile.include         |   3 +
 tools/tracing/rtla/.gitignore          |   1 +
 tools/tracing/rtla/Makefile            |  20 +-
 tools/tracing/rtla/Makefile.config     |  42 +++
 tools/tracing/rtla/Makefile.rtla       |  17 +-
 tools/tracing/rtla/src/Build           |   1 +
 tools/tracing/rtla/src/osnoise.c       |  86 +++++-
 tools/tracing/rtla/src/osnoise.h       |  50 ++++
 tools/tracing/rtla/src/osnoise_hist.c  | 124 ++-------
 tools/tracing/rtla/src/osnoise_top.c   | 126 +--------
 tools/tracing/rtla/src/timerlat.bpf.c  | 149 ++++++++++
 tools/tracing/rtla/src/timerlat.c      | 106 ++++++++
 tools/tracing/rtla/src/timerlat.h      |  54 ++++
 tools/tracing/rtla/src/timerlat_aa.c   |   2 -
 tools/tracing/rtla/src/timerlat_bpf.c  | 166 ++++++++++++
 tools/tracing/rtla/src/timerlat_bpf.h  |  59 ++++
 tools/tracing/rtla/src/timerlat_hist.c | 354 ++++++++++++------------
 tools/tracing/rtla/src/timerlat_top.c  | 482 ++++++++++++++++++---------------
 tools/tracing/rtla/src/trace.c         |   4 +
 tools/tracing/rtla/tests/engine.sh     |  66 +++++
 tools/tracing/rtla/tests/osnoise.t     |   6 +
 tools/tracing/rtla/tests/timerlat.t    |  14 +
 tools/verification/rv/Makefile.rv      |   2 +-
 25 files changed, 1315 insertions(+), 625 deletions(-)
 create mode 100644 tools/tracing/rtla/src/timerlat.bpf.c
 create mode 100644 tools/tracing/rtla/src/timerlat_bpf.c
 create mode 100644 tools/tracing/rtla/src/timerlat_bpf.h
---------------------------