[PoC PATCH v2 00/21] Add trace file compression

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

A new PoC implementation, adding a compression to trace file.
A basic infrastructure for compression support is added into the trace-cmd
library. The zlib is used for compression, but more libraries and algorithms
can be added. Only part of the trace file metadata is compressed: 
 - ftrace events format
 - format of recorded events
 - information about the mapping of function addresses to the function names
 - trace_printk() format strings
 - information of the mapping a PID to a process name
 - options

Note: not all trace-cmd commands are tested with these changes. These are
verified to work with compressed trace files:
 trace-cmd record
 trace-cmd report
 trace-cmd dump
 trace-cmd agent

Todo list, in order to have complete trace file compression:
 - Compress trace data.
 - Add support for more compression libraries.
 - Add new trace-cmd command to convert trace files from version 6 to
   version 7 and vise versa.
 - Test all trace-cmd commands with trace file v7.
 - Update trace-cmd documentation.

v2 changes:
 - Refactored compression APIs.
 - Moved the trace buffers description out of the trace options section.
 - Added compression of "options" section of the trace file.
 - Updated "trace-cmd list" to show available compression algorithms.
 - Tested with host-guest tracing.
 - Merged with the patchset that bumps the trace file version.

Tzvetomir Stoyanov (VMware) (21):
  trace-cmd library: Remove unused private APIs for creating trace files
  trace-cmd library: Remove unused API tracecmd_update_option
  trace-cmd: Check if file version is supported
  trace-cmd library: Add new API to get file version of input handler
  trace-cmd library: Select the file version when writing trace file
  trace-cmd: Add APIs for library initialization and free
  trace-cmd library: Add support for compression algorithms
  trace-cmd list: Show supported compression algorithms
  trace-cmd library: Bump the trace file version to 7
  trace-cmd library: Compress part of the trace file
  trace-cmd library: Read compressed trace file
  trace-cmd library: Add new API to get compression of input handler
  trace-cmd library: Inherit compression algorithm from input file
  trace-cmd library: Extend the create file APIs to support different
    compression
  trace-cmd record: Add new parameter --compression
  trace-cmd dump: Add support for trace files version 7
  trace-cmd library: Add support for zlib compression library
  trace-cmd library: Hide the logic for updating buffer offset
  trace-cmd: Move buffers description outside of options
  trace-cmd library: Track the offset in the option section in the trace
    file
  trace-cmd library: Add compression of the option section of the trace
    file

 lib/trace-cmd/Makefile                        |  11 +
 .../include/private/trace-cmd-private.h       |  71 ++-
 lib/trace-cmd/include/trace-cmd-local.h       |   9 +-
 lib/trace-cmd/trace-compress-zlib.c           | 172 ++++++
 lib/trace-cmd/trace-compress.c                | 543 ++++++++++++++++++
 lib/trace-cmd/trace-input.c                   | 375 +++++++++---
 lib/trace-cmd/trace-output.c                  | 541 ++++++++++++-----
 lib/trace-cmd/trace-util.c                    |  19 +
 tracecmd/trace-cmd.c                          |  11 +-
 tracecmd/trace-dump.c                         | 162 +++++-
 tracecmd/trace-list.c                         |  26 +
 tracecmd/trace-listen.c                       |   3 +
 tracecmd/trace-record.c                       |  42 +-
 tracecmd/trace-restore.c                      |   4 +-
 tracecmd/trace-usage.c                        |   6 +
 15 files changed, 1703 insertions(+), 292 deletions(-)
 create mode 100644 lib/trace-cmd/trace-compress-zlib.c
 create mode 100644 lib/trace-cmd/trace-compress.c

-- 
2.31.1