3932ef3ffb
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()
50 lines
1.2 KiB
Python
50 lines
1.2 KiB
Python
#!/usr/bin/env python
|
|
# -*- coding: utf-8 -*-
|
|
|
|
"""
|
|
Syslog built-in backend.
|
|
"""
|
|
|
|
__author__ = "Paul Durrant <paul.durrant@citrix.com>"
|
|
__copyright__ = "Copyright 2016, Citrix Systems Inc."
|
|
__license__ = "GPL version 2 or (at your option) any later version"
|
|
|
|
__maintainer__ = "Stefan Hajnoczi"
|
|
__email__ = "stefanha@redhat.com"
|
|
|
|
|
|
from tracetool import out
|
|
|
|
|
|
PUBLIC = True
|
|
|
|
|
|
def generate_h_begin(events, group):
|
|
out('#include <syslog.h>',
|
|
'')
|
|
|
|
|
|
def generate_h(event, group):
|
|
argnames = ", ".join(event.args.names())
|
|
if len(event.args) > 0:
|
|
argnames = ", " + argnames
|
|
|
|
if "vcpu" in event.properties:
|
|
# already checked on the generic format code
|
|
cond = "true"
|
|
else:
|
|
cond = "trace_event_get_state(%s)" % ("TRACE_" + event.name.upper())
|
|
|
|
out(' if (%(cond)s) {',
|
|
' syslog(LOG_INFO, "%(name)s " %(fmt)s %(argnames)s);',
|
|
' }',
|
|
cond=cond,
|
|
name=event.name,
|
|
fmt=event.fmt.rstrip("\n"),
|
|
argnames=argnames)
|
|
|
|
|
|
def generate_h_backend_dstate(event, group):
|
|
out(' trace_event_get_state_dynamic_by_id(%(event_id)s) || \\',
|
|
event_id="TRACE_" + event.name.upper())
|