bd82631d7c
Currently, sythetic events only support static string fields such as: # echo 'test_latency u64 lat; char somename[32]' > /sys/kernel/debug/tracing/synthetic_events Which is fine, but wastes a lot of space in the event. It also prevents the most commonly-defined strings in the existing trace events e.g. those defined using __string(), from being passed to synthetic events via the trace() action. With this change, synthetic events with dynamic fields can be defined: # echo 'test_latency u64 lat; char somename[]' > /sys/kernel/debug/tracing/synthetic_events And the trace() action can be used to generate events using either dynamic or static strings: # echo 'hist:keys=name:lat=common_timestamp.usecs-$ts0:onmatch(sys.event).test_latency($lat,name)' > /sys/kernel/debug/tracing/events The synthetic event dynamic strings are implemented in the same way as the existing __data_loc strings and appear as such in the format file. [ <rostedt@goodmis.org>: added __set_synth_event_print_fmt() changes: I added the following to make it work with trace-cmd. Dynamic strings must have __get_str() for events in the print_fmt otherwise it can't be parsed correctly. ] Link: https://lore.kernel.org/r/cover.1601588066.git.zanussi@kernel.org Link: https://lkml.kernel.org/r/3ed35b6d0e390f5b94cb4a9ba1cc18f5982ab277.1601848695.git.zanussi@kernel.org Tested-by: Axel Rasmussen <axelrasmussen@google.com> Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
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.. | ||
blktrace.c | ||
bpf_trace.c | ||
bpf_trace.h | ||
fgraph.c | ||
ftrace_internal.h | ||
ftrace.c | ||
Kconfig | ||
kprobe_event_gen_test.c | ||
Makefile | ||
power-traces.c | ||
preemptirq_delay_test.c | ||
ring_buffer_benchmark.c | ||
ring_buffer.c | ||
rpm-traces.c | ||
synth_event_gen_test.c | ||
trace_benchmark.c | ||
trace_benchmark.h | ||
trace_boot.c | ||
trace_branch.c | ||
trace_clock.c | ||
trace_dynevent.c | ||
trace_dynevent.h | ||
trace_entries.h | ||
trace_event_perf.c | ||
trace_events_filter_test.h | ||
trace_events_filter.c | ||
trace_events_hist.c | ||
trace_events_inject.c | ||
trace_events_synth.c | ||
trace_events_trigger.c | ||
trace_events.c | ||
trace_export.c | ||
trace_functions_graph.c | ||
trace_functions.c | ||
trace_hwlat.c | ||
trace_irqsoff.c | ||
trace_kdb.c | ||
trace_kprobe_selftest.c | ||
trace_kprobe_selftest.h | ||
trace_kprobe.c | ||
trace_mmiotrace.c | ||
trace_nop.c | ||
trace_output.c | ||
trace_output.h | ||
trace_preemptirq.c | ||
trace_printk.c | ||
trace_probe_tmpl.h | ||
trace_probe.c | ||
trace_probe.h | ||
trace_sched_switch.c | ||
trace_sched_wakeup.c | ||
trace_selftest_dynamic.c | ||
trace_selftest.c | ||
trace_seq.c | ||
trace_stack.c | ||
trace_stat.c | ||
trace_stat.h | ||
trace_synth.h | ||
trace_syscalls.c | ||
trace_uprobe.c | ||
trace.c | ||
trace.h | ||
tracing_map.c | ||
tracing_map.h |