On Thu, 31 Mar 2022 20:09:25 -0700 Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > @@ -5908,6 +5910,8 @@ > trace_buf_size=nn[KMG] > [FTRACE] will set tracing buffer size on each cpu. > > + trace_clock= [FTRACE] See Documentation/trace/ftrace.rst trace_clock= [FTRACE] Set the clock used for tracing events at boot up. local - Use the per CPU time stamp counter (converted into nanoseconds). Fast, but depending on the architecture, may not be in sync between CPUs. global - Event time stamps are synchronize across CPUs. May be slower than the local clock, but better for some race conditions. counter - Simple counting of events (1, 2, ..) note, some counts may be skipped due to the infrastructure grabbing the clock more than once per event. uptime - Use jiffies as the time stamp. perf - Use the same clock that perf uses. mono - Use ktime_get_mono_fast_ns() for time stamps. mono_raw - Use ktime_get_raw_fast_ns() for time stamps. boot - Use ktime_get_boot_fast_ns() for time stamps. Architectures may add more clocks. See Documentation/trace/ftrace.rst for more details. -- Steve > + > trace_event=[event-list] > [FTRACE] Set and start specified trace events in order > to facilitate early boot debugging. The event-list is a
