[RFC,v9,00/11] Add VM kernel tracing over vsockets and FIFOs

Message

Slavomir Kaslev April 2, 2019, 1:45 p.m. UTC

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

Changes in v9:
 - none

Changes in v8:
 - switched protocol message encoding of ports to text
 - switched ports data type to unsigned since vsockets port numbers can overflow int and be confused with errors codes by other code
 - added automatic naming for guests with no names (for VMware Workstation guests currently)
 - added --debug option to trace-cmd agent

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 (10):
  trace-cmd: Make ports unsigned int
  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

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

 Makefile                       |   7 +
 include/trace-cmd/trace-cmd.h  |  18 +-
 lib/trace-cmd/trace-recorder.c | 129 ++++--
 tracecmd/Makefile              |   5 +
 tracecmd/include/trace-local.h |  29 ++
 tracecmd/trace-agent.c         | 294 +++++++++++++
 tracecmd/trace-cmd.c           |   4 +
 tracecmd/trace-listen.c        |  10 +-
 tracecmd/trace-msg.c           | 249 ++++++++++-
 tracecmd/trace-record.c        | 773 +++++++++++++++++++++++++++++++--
 tracecmd/trace-setup-guest.c   | 247 +++++++++++
 tracecmd/trace-usage.c         |  22 +-
 12 files changed, 1695 insertions(+), 92 deletions(-)
 create mode 100644 tracecmd/trace-agent.c
 create mode 100644 tracecmd/trace-setup-guest.c

--
2.19.1