[RFC,v8,00/13] Add VM kernel tracing over vsockets and FIFOs

Message

Slavomir Kaslev Feb. 22, 2019, 6:05 p.m. UTC

This patchset adds support for tracing guest kernels to trace-cmd.

The first two patches in the series are minor cleanups which can be merged
separately.

Changes in v8:
 - refactored make_dir function per Steven's review feedback

Changes in v7:
 - fixed potential memory leak in add_arg()
 - call msg_free() in tracecmd_msg_recv_trace_req() eventhough we're stealing
   the message buffer
 - added is_guest and is_agent macros and use throughout tracecmd_record.c
   instead of testing instance->flags bits
 - avoid memory allocation in make_dir()

Changes in v6:
 - added specialized data transfer path over FIFOs making single splice() per
   iteration
 - made tracecmd_msg_recv_trace_req/tracecmd_msg_recv_trace_resp more defensive
   to invalid messages

Changes in v5:
 - add FIFOs transport for tracing data
 - fixed a bug in tracecmd_msg_wait_close

Changes in v4:
 - detect and use splice(2) on vsock sockets if possible
 - switch port numbers to unsigned int
 - trace-cmd record --date flag is now set for all guests if provided by the user
 - removed grow_cap and exponential buffer size growth

Changes in v3:
 - addressed Steven's feedback
 - detect and disable guest tracing if <linux/vm_sockets.h> is not available
 - the --date flag is now treated as global for all guest instances
 - fixed a bug that caused --date to be ignored for host tracing data when tracing guests

Changes in v2:
 - rebased on top of protocol V3
 - fixed system clock timestamps with the --date flag


Slavomir Kaslev (12):
  trace-cmd: Minor cleanup in tracecmd_start_recording()
  trace-cmd: Minor cleanup in print_stat()
  trace-cmd: Add tracecmd_create_recorder_virt function
  trace-cmd: Add TRACE_REQ and TRACE_RESP messages
  trace-cmd: Add buffer instance flags for tracing in guest and agent
    context
  trace-cmd: Add VM kernel tracing over vsockets transport
  trace-cmd: Use splice(2) for vsockets if available
  trace-cmd: Add `trace-cmd setup-guest` command
  trace-cmd: Try to autodetect number of guest CPUs in setup-guest if
    not specified
  trace-cmd: Add setup-guest flag for attaching FIFOs to the guest VM
    config
  trace-cmd: Add splice() recording from FIFO without additional pipe
    buffer
  trace-cmd: Add VM tracing over FIFOs transport

Steven Rostedt (VMware) (1):
  trace-cmd: Detect if vsockets are available

 Makefile                       |   7 +
 include/trace-cmd/trace-cmd.h  |  16 +-
 lib/trace-cmd/trace-recorder.c | 140 ++++--
 tracecmd/Makefile              |   7 +-
 tracecmd/include/trace-local.h |  29 ++
 tracecmd/trace-agent.c         | 257 +++++++++++
 tracecmd/trace-cmd.c           |   4 +
 tracecmd/trace-msg.c           | 219 ++++++++-
 tracecmd/trace-record.c        | 779 ++++++++++++++++++++++++++++++---
 tracecmd/trace-setup-guest.c   | 247 +++++++++++
 tracecmd/trace-usage.c         |  22 +-
 11 files changed, 1639 insertions(+), 88 deletions(-)
 create mode 100644 tracecmd/trace-agent.c
 create mode 100644 tracecmd/trace-setup-guest.c