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The fgraph "sleep-time" option tells the function graph tracer and the profiler whether to include the time a function "sleeps" (is scheduled off the CPU) in its duration for the function. By default it is true, which means the duration of a function is calculated by the timestamp of when the function was entered to the timestamp of when it exits. If the "sleep-time" option is disabled, it needs to remove the time that the task was not running on the CPU during the function. Currently it is done in a sched_switch tracepoint probe where it moves the "calltime" (time of entry of the function) forward by the sleep time calculated. It updates all the calltime in the shadow stack. This is time consuming for those users of the function graph tracer that does not care about the sleep time. Instead, add a "ftrace_sleeptime" to the task_struct that gets the sleep time added each time the task wakes up. Then have the function entry save the current "ftrace_sleeptime" and on function exit, move the calltime forward by the difference of the current "ftrace_sleeptime" from the saved sleeptime. This removes one dependency of "calltime" needed to be on the shadow stack. It also simplifies the code that removes the sleep time of functions. TODO: Only enable the sched_switch tracepoint when this is needed. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jiri Olsa <olsajiri@gmail.com> Link: https://lore.kernel.org/20240914214826.938908568@goodmis.org Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
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| .. | ||
| rv | ||
| blktrace.c | ||
| bpf_trace.c | ||
| bpf_trace.h | ||
| error_report-traces.c | ||
| fgraph.c | ||
| fprobe.c | ||
| ftrace_internal.h | ||
| ftrace.c | ||
| Kconfig | ||
| kprobe_event_gen_test.c | ||
| Makefile | ||
| pid_list.c | ||
| pid_list.h | ||
| power-traces.c | ||
| preemptirq_delay_test.c | ||
| rethook.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_btf.c | ||
| trace_btf.h | ||
| trace_clock.c | ||
| trace_dynevent.c | ||
| trace_dynevent.h | ||
| trace_entries.h | ||
| trace_eprobe.c | ||
| 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_user.c | ||
| trace_events.c | ||
| trace_export.c | ||
| trace_fprobe.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_osnoise.c | ||
| trace_output.c | ||
| trace_output.h | ||
| trace_preemptirq.c | ||
| trace_printk.c | ||
| trace_probe_kernel.h | ||
| trace_probe_tmpl.h | ||
| trace_probe.c | ||
| trace_probe.h | ||
| trace_recursion_record.c | ||
| 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 | ||