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Date: Fri, 19 Jan 2024 11:56:25 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Huang Yiwei <quic_hyiwei@quicinc.com>
Cc: <mhiramat@kernel.org>, <mark.rutland@arm.com>, <mcgrof@kernel.org>,
 <keescook@chromium.org>, <j.granados@samsung.com>,
 <mathieu.desnoyers@efficios.com>, <corbet@lwn.net>,
 <linux-kernel@vger.kernel.org>, <linux-trace-kernel@vger.kernel.org>,
 <linux-fsdevel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
 <quic_bjorande@quicinc.com>, <quic_tsoni@quicinc.com>,
 <quic_satyap@quicinc.com>, <quic_aiquny@quicinc.com>, <kernel@quicinc.com>,
 Ross Zwisler <zwisler@google.com>, Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v3] tracing: Support to dump instance traces by
 ftrace_dump_on_oops
Message-ID: <20240119115625.603188d1@gandalf.local.home>
In-Reply-To: <20240119080824.907101-1-quic_hyiwei@quicinc.com>
References: <20240119080824.907101-1-quic_hyiwei@quicinc.com>
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On Fri, 19 Jan 2024 16:08:24 +0800
Huang Yiwei <quic_hyiwei@quicinc.com> wrote:

> -	ftrace_dump_on_oops[=orig_cpu]
> +	ftrace_dump_on_oops[=orig_cpu | =<instance>]

I wonder if we should have it be:

	ftrace_dump_on_oops[=orig_cpu | =<instance> | =<instance>:orig_cpu ]

Then last would be to only print out a specific CPU trace of the given instance.

And if we really want to be fancy!

	ftrace_dump_on_opps[=orig_cpu | =<instance> | =orig_cpu:<instance> ][,<instance> | ,<instance>:orig_cpu]

That would allow dumping more than one instance.

If you want to dump the main buffer and an instance foo:

	ftrace_dump_on_opps,foo

Where the ',' says to dump the top instance as well as the foo instance.

-- Steve


>  			[FTRACE] will dump the trace buffers on oops.
> -			If no parameter is passed, ftrace will dump
> -			buffers of all CPUs, but if you pass orig_cpu, it will
> +			If no parameter is passed, ftrace will dump global
> +			buffers of all CPUs, if you pass orig_cpu, it will
>  			dump only the buffer of the CPU that triggered the
> -			oops.
> +			oops, or specific instance will be dumped if instance
> +			name is passed.
>