[ANNOUNCE] trace-cmd 3.0

[ANNOUNCE] trace-cmd 3.0

[Steven Rostedt]

[ Resending without corrupted email headers ]

I'm happy to announce that after over a year, we finally are able to
release trace-cmd version 3.0!

The two biggest changes:

1) Updated trace.dat to version 7 (not compatible with older versions of
   trace-cmd). But now supports compression.

2) Better synchronization between host and guest kernel tracing.


Features and user visible updates since 2.9:

- Relies on upstream repos for libtraceevent and libtracefs:
    * Removed libtraceevent code (Upstream minimum version 1.5)
    * Removed libtracefs code (Upstream minimum version 1.3)

- KernelShark is no longer installed in the trace-cmd repo.

- Some perf support

- trace-cmd dump updates:
   * Display the clock used in the file

- New trace-cmd clock: tsc2nsec to use the tsc clock in the ring buffer but
  to display it as nanoseconds. Requires architecture support, but trace-cmd
  list -C will show if it supported or not.

- New option --raw-ts for trace-cmd report to show raw timestamps without any
  modifications.

- New timestamp synchronization between host and guests.
   * P2P : timing back and forth of host and guest
   * KVM : queries the kernel for the multiplier, offset and shift for exact
           synchronization of host and guest timestamps.

- tracecmd_warning() API for writing error messages in libtracecmd library.

- Better bash tab completion.

- Plugins now go into /usr/[local/]lib/trace-cmd instead of traceevent
  directory.

- New option --full for trace-cmd list to show "print fmt" of event formats
  specified by -e <event> -F

- trace-cmd list now shows ftrace events as well as events that can be
  enabled.

- Supports non qemu VM host/guest tracing.

- New option --align-ts for trace-cmd report that will make the timestamps of
  all events a delta from the first event. (0.000003 instead of 16292.633984)

- New option -V for trace-cmd report to change verbosity.

- New option --verbose for a bunch of commands to trace-cmd.

- New option --poll for trace-cmd record to poll which makes trace-cmd check
  the buffers with O_NONBLOCK instead of relying on IPIs to wake it up. This
  reduces latency on recording tasks that trace-cmd is not running on.

- trace.dat output has been updated to Version 7 (incompatible with older
  trace-cmd, but trace-cmd convert can convert back to version 6, with
  possible lost of features).
   * The file is broken up into sections (defined as options) just like an ELF
     file.
   * Allows for sections to be compressed.
      .  Supports zlib compression
      .  Supports ZSTD compression
   * Will allow for new types of data to be added
      . Target for perf data to be included (still in development)

- New command: trace-cmd convert, to convert between trace-cmd 7 and 6 files.