On Mon, Jul 31, 2017 at 03:07:16PM +0100, Stefan Hajnoczi wrote: > v2: > * Don't special-case QEMU dstate [Daniel Berrange] > * Use _backends() postfix to clarify function purpose [Lluís] > > Trace events that compute their arguments can affect performance. The > following idom can be used to avoid computing arguments when the trace event > is > disabled: > > if (trace_event_get_state(TRACE_MY_EVENT)) { > char *str = g_strdup_printf("Expensive string ...", ...); > trace_my_event(str); > g_free(str); > } > > Unfortunately this breaks the trace event for SystemTap and LTTng UST since > those tracers manage their own enabled/disabled state. > > These patches add per-backend dstate to trace_event_get_state() so that the > trace event fires as expected when enabled via SystemTap or LTTng UST. > > Stefan Hajnoczi (2): > trace: add TRACE_<event>_BACKEND_DSTATE() > trace: add trace_event_get_state_backends() > > docs/devel/tracing.txt | 2 +- > trace/control.h | 18 +++++++++++++++++- > hw/usb/hcd-ohci.c | 13 +++++-------- > net/colo-compare.c | 11 ++++++----- > net/filter-rewriter.c | 4 ++-- > 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 | 5 +++++ > scripts/tracetool/format/h.py | 10 ++++++++++ > 14 files changed, 82 insertions(+), 17 deletions(-) > > -- > 2.13.3 > >
Thanks, applied to my tracing tree: https://github.com/stefanha/qemu/commits/tracing Stefan
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