[Qemu-commits] [qemu/qemu] 9f591a: trace: Clarify DTrace/SystemTap help message

[Peter Maydell]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: 9f591a5d95e1969969632ab44cf35e505c8ddc3b
      
https://github.com/qemu/qemu/commit/9f591a5d95e1969969632ab44cf35e505c8ddc3b
  Author: Philippe Mathieu-Daudé <address@hidden>
  Date:   2019-08-27 (Tue, 27 Aug 2019)

  Changed paths:
    M trace/control.c

  Log Message:
  -----------
  trace: Clarify DTrace/SystemTap help message

Most tracing backends are implemented within QEMU, except the
DTrace/SystemTap backends.

One side effect is when running 'qemu -trace help', an incomplete
list of trace events is displayed when using the DTrace/SystemTap
backends.

This is partly due to trace events registered as modules with
trace_init(), and since the events are not used within QEMU,
the linker optimize and remove the unused modules (which is
OK in this particular case).
Currently only the events compiled in trace-root.o and in the
last trace.o member of libqemuutil.a are linked, resulting in
an incomplete list of events.

To avoid confusion, improve the help message, recommending to
use the proper systemtap script to display the events list.

Before:

  $ lm32-softmmu/qemu-system-lm32 -trace help 2>&1 | wc -l
  70

After:

  $ lm32-softmmu/qemu-system-lm32 -trace help
  Run 'qemu-trace-stap list qemu-system-lm32' to print a list
  of names of trace points with the DTrace/SystemTap backends.

  $ qemu-trace-stap list qemu-system-lm32 | wc -l
  1136

Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
Message-id: address@hidden
Message-Id: <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>


  Commit: cc6613e244e86c66f83467eab5284825d7057cea
      
https://github.com/qemu/qemu/commit/cc6613e244e86c66f83467eab5284825d7057cea
  Author: Peter Maydell <address@hidden>
  Date:   2019-09-03 (Tue, 03 Sep 2019)

  Changed paths:
    M trace/control.c

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' 
into staging

Pull request

# gpg: Signature made Tue 27 Aug 2019 21:33:15 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <address@hidden>" [full]
# gpg:                 aka "Stefan Hajnoczi <address@hidden>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: Clarify DTrace/SystemTap help message

Signed-off-by: Peter Maydell <address@hidden>


Compare: https://github.com/qemu/qemu/compare/54b89db5309d...cc6613e244e8