This is a very basic example, demonsting the usage of the new APIs for kernel synth. events. Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx> --- examples/synth.py | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100755 examples/synth.py diff --git a/examples/synth.py b/examples/synth.py new file mode 100755 index 0000000..ec9427b --- /dev/null +++ b/examples/synth.py @@ -0,0 +1,43 @@ +#!/usr/bin/env python3 + +""" +SPDX-License-Identifier: CC-BY-4.0 + +Copyright 2021 VMware Inc, Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx> +""" + +import tracecruncher.ftracepy as ft + +# Define a synthetic event that combines 'sched_waking' and 'sched_switch'. +# A synth. event will be recorded every time a 'start' event (sched_waking) +# is followed by an 'end' event (sched_switch) and both events have the same +# value of the fields 'pid' and 'next_pid' (belong to the same process). +synth = ft.synth(name='synth_wakeup', + start_sys='sched', start_evt='sched_waking', + end_sys='sched', end_evt='sched_switch', + start_match='pid', end_match='next_pid', + match_name='pid') + +# Add to the synth. event two fields from the 'start' event. In the synth. event, +# the field 'target_cpu' will be renamed to 'cpu'. +synth.add_start_fields(fields=['target_cpu', 'prio'], + names=['cpu', None]) + +# Add to the synth. event one field from the 'end' event. +synth.add_end_fields(fields=['next_prio']) + +# Add to the synth. event a field that measures the time-difference between +# the 'start' and 'end' events. Use 'hd' time resolution (nanoseconds). +synth.add_delta_T(hd=True) + +# Register the synth. event on the system. +synth.register() + +inst = ft.create_instance() + +# Apply a filter and enable the synth. event. +synth.set_filter(instance=inst, filter='prio<100') +synth.enable(instance=inst) + +# Print the stream of trace events. "Ctrl+c" to stop tracing. +ft.read_trace(instance=inst) -- 2.32.0
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