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Date: Wed, 16 Apr 2025 11:12:27 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH] tracing: Record trace_clock in last_boot_info
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In-Reply-To: <174481479787.2426861.10924329074660376176.stgit@mhiramat.tok.corp.google.com>
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On Wed, 16 Apr 2025 23:46:38 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> Record trace_clock information in the trace_scratch area and show
> it via `last_boot_info` so that reader can docode the timestamp
> correctly.
> With this change, the first line of the last_boot_info becomes
> trace_clock which is used when the trace was recorded. E.g.
> 
> /sys/kernel/tracing/instances/boot_mapped # cat last_boot_info
> trace_clock: mono
> ffffffff81000000        [kernel]
> 

As this will not go in this cycle, which means tools may be built
around this.

Either we put it at the end, or we make it:

# trace_clock: mono
ffffffff81000000        [kernel]

Where "info" like "trace_clock" will be in the comment section, and all
non comments will be addresses.

Tooling can then just ignore the comment section, or read it for more
information.

-- Steve