Re: [PATCH V6 0/3] Integration of function trace with System Trace IP blocks

From: Chunyan Zhang <zhang.chunyan@linaro.org>
To: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	mingo@redhat.com, Arnd Bergmann <arnd@arndb.de>,
	Mike Leach <mike.leach@arm.com>, Tor Jeremiassen <tor@ti.com>,
	philippe.langlais@st.com, Nicolas GUION <nicolas.guion@st.com>,
	Lyra Zhang <zhang.lyra@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH V6 0/3] Integration of function trace with System Trace IP blocks
Date: Thu, 8 Sep 2016 21:09:27 +0800	[thread overview]
Message-ID: <CAG2=9p9d5qH9Ty3Lwh5v4z4uy078XKyw4ooJG5yXkZfFdaoOgQ@mail.gmail.com> (raw)
In-Reply-To: <87inu6h9xz.fsf@linux.intel.com>

Hi Balbi,

On 8 September 2016 at 20:07, Felipe Balbi <felipe.balbi@linux.intel.com> wrote:
>
> Hi,
>
> Chunyan Zhang <zhang.chunyan@linaro.org> writes:
>> IP blocks allowing a variety of trace sources to log debugging
>> information to a pre-defined area have been introduced on a couple of
>> architecture [1][2]. These system trace blocks (also known as STM)
>> typically follow the MIPI STPv2 protocol [3] and provide a system wide
>> logging facility to any device, running a kernel or not, with access
>> to the block's log entry port(s).  Since each trace message has a
>> timestamp, it is possible to correlate events happening in the entire
>> system rather than being confined to the logging facility of a single
>> entity.
>>
>> This patchset is trying to use STM IP blocks to store function tracing
>> information produced by Ftrace and I'm taking the Function trace
>> (trace type is TRACE_FN) as the example in this patchset, but other
>> types of traces also can be supported.
>>
>> Logging information generated by the Ftrace subsystem to STM and gathered
>> in the sink device can be used in conjunction with trace data from other
>> board components, also collected in the same trace sink.
>>
>> This example is using ARM coresight STM but the same would apply to any
>> other architecture wishing to do the same.
>>
>> Comments would be greatly appreciated.
>
> showing up late to the bandwagon, but this is very good. I've been
> toying with the idea of exporting ftrace via USB and this will help
> quite a bit. Thanks :-)

Very happy this work may be helpful for you.

>
> I'll add to my TODO a look at this series. Great work.

Yes, please help review, comments are very welcome.

There's still some other work related this need to be done, this
patch-set is the first step.  I will keep you posted with any update.

Thanks,
Chunyan

>
> --
> balbi