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SubjectRe: [PATCH 1/3 v2] Docs: admin/kernel-parameters: edit a few boot options
On Thu, 31 Mar 2022 20:09:25 -0700
Randy Dunlap <rdunlap@infradead.org> 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

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