QEMU keeps track of trace event enabled/disabled state and provides
monitor commands to inspect and modify the "dstate". SystemTap and
LTTng UST maintain independent enabled/disabled states for each trace
event, the other backends rely on QEMU dstate.
Introduce a new per-event macro that combines backend-specific dstate
like this:
#define TRACE_MY_EVENT_BACKEND_DSTATE() ( \
QEMU_MY_EVENT_ENABLED() || /* SystemTap */ \
tracepoint_enabled(qemu, my_event) /* LTTng UST */ || \
false)
This will be used to extend trace_event_get_state() in the next patch.
[Daniel Berrange pointed out that QEMU_MY_EVENT_ENABLED() must be true
by default, not false. This way events will fire even if the DTrace
implementation does not implement the SystemTap semaphores feature.
Ubuntu Precise uses lttng-ust-dev 2.0.2 which does not have
tracepoint_enabled(), so we need a compatibility wrapper to keep Travis
builds passing.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
fixup! trace: add TRACE_<event>_BACKEND_DSTATE()
Last patch removed a nesting level in generated code. Re-align all code
generated by backends to be 4-column aligned.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-id: 149915824586.6295.17820926011082409033.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Introduce rules in the top level Makefile that are able to generate
trace.[ch] files in every subdirectory which has a trace-events file.
The top level directory is handled specially, so instead of creating
trace.h, it creates trace-root.h. This allows sub-directories to
include the top level trace-root.h file, without ambiguity wrt to
the trace.g file in the current sub-dir.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170125161417.31949-7-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The declarations in the generated-tracers.h file are
assuming there's only ever going to be one instance
of this header, as they are not namespaced. When we
have one header per event group, if a single source
file needs to include multiple sets of trace events,
the symbols will all clash.
This change thus introduces a '--group NAME' arg to the
'tracetool' program. This will cause all the symbols in
the generated header files to be given a unique namespace.
If no group is given, the group name 'common' is used,
which is suitable for the current usage where there is
only one global trace-events file used for code generation.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 1475588159-30598-21-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Events with the 'vcpu' property are conditionally emitted according to
their per-vCPU state. Other events are emitted normally based on their
global tracing state.
Note that the per-vCPU condition check applies to all tracing backends.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Backends now only contain the essential backend-specific code, and most of the work is moved to frontend code.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Makes it easier to ensure proper naming across the different frontends and backends.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Public backends are those printed by "--list-backends" and thus considered valid
by the configure script.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
--
Changes in v2:
* Do not depend on "qemu-timer-common.o".
* Use "$(obj)" in rules to refer to the build sub-directory.
* Remove dependencies against "$(GENERATED_HEADERS)".
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Over time various systemtap reserved words have been blacklisted
in the trace backend generator. The list is not complete though,
so there is continued risk of problems in the future. Preempt
such problems by specifying the full list of systemtap keywords
listed in its parser as identified here:
http://sourceware.org/ml/systemtap/2012-q4/msg00157.html
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Language keywords cannot be used as argument names. The DTrace backend
appends an underscore to the argument name in order to make the argument
name legal.
This patch adds 'in', 'next', and 'self' keywords to dtrace.py.
Also drop the unnecessary argument name lstrip() call. The
Arguments.build() method already ensures there is no space around
argument names. Furthermore it is misleading to do the lstrip() *after*
checking against keywords because the keyword check would not match if
spaces were in the name.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Alon Levy <alevy@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
