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()
101 lines
2.8 KiB
Python
101 lines
2.8 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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trace/generated-tracers.h
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"""
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__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
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__copyright__ = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"
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__license__ = "GPL version 2 or (at your option) any later version"
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__maintainer__ = "Stefan Hajnoczi"
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__email__ = "stefanha@linux.vnet.ibm.com"
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from tracetool import out
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def generate(events, backend, group):
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out('/* This file is autogenerated by tracetool, do not edit. */',
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'',
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'#ifndef TRACE_%s_GENERATED_TRACERS_H' % group.upper(),
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'#define TRACE_%s_GENERATED_TRACERS_H' % group.upper(),
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'',
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'#include "qemu-common.h"',
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'#include "trace/control.h"',
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'')
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for e in events:
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out('extern TraceEvent %(event)s;',
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event = e.api(e.QEMU_EVENT))
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for e in events:
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out('extern uint16_t %s;' % e.api(e.QEMU_DSTATE))
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# static state
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for e in events:
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if 'disable' in e.properties:
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enabled = 0
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else:
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enabled = 1
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if "tcg-exec" in e.properties:
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# a single define for the two "sub-events"
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out('#define TRACE_%(name)s_ENABLED %(enabled)d',
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name=e.original.name.upper(),
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enabled=enabled)
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out('#define TRACE_%s_ENABLED %d' % (e.name.upper(), enabled))
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backend.generate_begin(events, group)
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for e in events:
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# tracer-specific dstate
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out('',
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'#define %(api)s() ( \\',
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api=e.api(e.QEMU_BACKEND_DSTATE))
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if "disable" not in e.properties:
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backend.generate_backend_dstate(e, group)
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out(' false)')
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# tracer without checks
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out('',
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'static inline void %(api)s(%(args)s)',
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'{',
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api=e.api(e.QEMU_TRACE_NOCHECK),
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args=e.args)
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if "disable" not in e.properties:
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backend.generate(e, group)
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out('}')
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# tracer wrapper with checks (per-vCPU tracing)
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if "vcpu" in e.properties:
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trace_cpu = next(iter(e.args))[1]
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cond = "trace_event_get_vcpu_state(%(cpu)s,"\
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" TRACE_%(id)s)"\
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% dict(
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cpu=trace_cpu,
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id=e.name.upper())
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else:
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cond = "true"
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out('',
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'static inline void %(api)s(%(args)s)',
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'{',
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' if (%(cond)s) {',
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' %(api_nocheck)s(%(names)s);',
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' }',
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'}',
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api=e.api(),
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api_nocheck=e.api(e.QEMU_TRACE_NOCHECK),
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args=e.args,
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names=", ".join(e.args.names()),
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cond=cond)
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backend.generate_end(events, group)
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out('#endif /* TRACE_%s_GENERATED_TRACERS_H */' % group.upper())
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