From 3932ef3ffb54baf22ab05767e827bda1834d20df Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 31 Jul 2017 15:07:17 +0100 Subject: trace: add TRACE__BACKEND_DSTATE() 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 Message-id: 20170731140718.22010-2-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi fixup! trace: add TRACE__BACKEND_DSTATE() --- scripts/tracetool/__init__.py | 1 + scripts/tracetool/backend/__init__.py | 3 +++ scripts/tracetool/backend/dtrace.py | 12 ++++++++++++ scripts/tracetool/backend/ftrace.py | 5 +++++ scripts/tracetool/backend/log.py | 5 +++++ scripts/tracetool/backend/simple.py | 5 +++++ scripts/tracetool/backend/syslog.py | 5 +++++ scripts/tracetool/backend/ust.py | 10 ++++++++++ scripts/tracetool/format/h.py | 10 ++++++++++ 9 files changed, 56 insertions(+) diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py index d4c204a472..0670ec17d5 100644 --- a/scripts/tracetool/__init__.py +++ b/scripts/tracetool/__init__.py @@ -271,6 +271,7 @@ class Event(object): QEMU_TRACE_NOCHECK = "_nocheck__" + QEMU_TRACE QEMU_TRACE_TCG = QEMU_TRACE + "_tcg" QEMU_DSTATE = "_TRACE_%(NAME)s_DSTATE" + QEMU_BACKEND_DSTATE = "TRACE_%(NAME)s_BACKEND_DSTATE" QEMU_EVENT = "_TRACE_%(NAME)s_EVENT" def api(self, fmt=None): diff --git a/scripts/tracetool/backend/__init__.py b/scripts/tracetool/backend/__init__.py index f735a259c0..259c6a6531 100644 --- a/scripts/tracetool/backend/__init__.py +++ b/scripts/tracetool/backend/__init__.py @@ -119,5 +119,8 @@ class Wrapper: def generate(self, event, group): self._run_function("generate_%s", event, group) + def generate_backend_dstate(self, event, group): + self._run_function("generate_%s_backend_dstate", event, group) + def generate_end(self, events, group): self._run_function("generate_%s_end", events, group) diff --git a/scripts/tracetool/backend/dtrace.py b/scripts/tracetool/backend/dtrace.py index c6812b70a2..c2f3a4e5a8 100644 --- a/scripts/tracetool/backend/dtrace.py +++ b/scripts/tracetool/backend/dtrace.py @@ -44,8 +44,20 @@ def generate_h_begin(events, group): out('#include "%s"' % header, '') + # SystemTap defines __ENABLED() but other DTrace + # implementations might not. + for e in events: + out('#ifndef QEMU_%(uppername)s_ENABLED', + '#define QEMU_%(uppername)s_ENABLED() true', + '#endif', + uppername=e.name.upper()) def generate_h(event, group): out(' QEMU_%(uppername)s(%(argnames)s);', uppername=event.name.upper(), argnames=", ".join(event.args.names())) + + +def generate_h_backend_dstate(event, group): + out(' QEMU_%(uppername)s_ENABLED() || \\', + uppername=event.name.upper()) diff --git a/scripts/tracetool/backend/ftrace.py b/scripts/tracetool/backend/ftrace.py index dd0eda4441..92f71b28f9 100644 --- a/scripts/tracetool/backend/ftrace.py +++ b/scripts/tracetool/backend/ftrace.py @@ -45,3 +45,8 @@ def generate_h(event, group): event_id="TRACE_" + event.name.upper(), 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()) diff --git a/scripts/tracetool/backend/log.py b/scripts/tracetool/backend/log.py index 54f0a69886..da86f6b882 100644 --- a/scripts/tracetool/backend/log.py +++ b/scripts/tracetool/backend/log.py @@ -48,3 +48,8 @@ def generate_h(event, group): 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()) diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py index f983670ee1..c2fd1c24c4 100644 --- a/scripts/tracetool/backend/simple.py +++ b/scripts/tracetool/backend/simple.py @@ -42,6 +42,11 @@ def generate_h(event, group): args=", ".join(event.args.names())) +def generate_h_backend_dstate(event, group): + out(' trace_event_get_state_dynamic_by_id(%(event_id)s) || \\', + event_id="TRACE_" + event.name.upper()) + + def generate_c_begin(events, group): out('#include "qemu/osdep.h"', '#include "trace/control.h"', diff --git a/scripts/tracetool/backend/syslog.py b/scripts/tracetool/backend/syslog.py index 1ce627f0fc..668fb73fee 100644 --- a/scripts/tracetool/backend/syslog.py +++ b/scripts/tracetool/backend/syslog.py @@ -42,3 +42,8 @@ def generate_h(event, group): 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()) diff --git a/scripts/tracetool/backend/ust.py b/scripts/tracetool/backend/ust.py index 2adaf548d5..280cb7c106 100644 --- a/scripts/tracetool/backend/ust.py +++ b/scripts/tracetool/backend/ust.py @@ -27,6 +27,11 @@ def generate_h_begin(events, group): out('#include ', '#include "%s"' % header, + '', + '/* tracepoint_enabled() was introduced in LTTng UST 2.7 */', + '#ifndef tracepoint_enabled', + '#define tracepoint_enabled(a, b) true', + '#endif', '') @@ -38,3 +43,8 @@ def generate_h(event, group): out(' tracepoint(qemu, %(name)s%(tp_args)s);', name=event.name, tp_args=argnames) + + +def generate_h_backend_dstate(event, group): + out(' tracepoint_enabled(qemu, %(name)s) || \\', + name=event.name) diff --git a/scripts/tracetool/format/h.py b/scripts/tracetool/format/h.py index aecf249d66..e06f0f27c5 100644 --- a/scripts/tracetool/format/h.py +++ b/scripts/tracetool/format/h.py @@ -49,6 +49,16 @@ def generate(events, backend, group): backend.generate_begin(events, group) for e in events: + # tracer-specific dstate + out('', + '#define %(api)s() ( \\', + api=e.api(e.QEMU_BACKEND_DSTATE)) + + if "disable" not in e.properties: + backend.generate_backend_dstate(e, group) + + out(' false)') + # tracer without checks out('', 'static inline void %(api)s(%(args)s)', -- cgit v1.2.1