Messages in this thread | | | From | Felipe Balbi <> | Subject | Re: [PATCH] usb: gadget: functions: add ftrace export over USB | Date | Fri, 14 Jul 2017 09:53:44 +0300 |
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Hi,
Pratyush Anand <panand@redhat.com> writes: > On Friday 09 June 2017 03:58 PM, Felipe Balbi wrote: >> Felipe Balbi <felipe.balbi@linux.intel.com> writes: >> >>> Allow for ftrace data to be exported over a USB Gadget >>> Controller. With this, we have a potentially very fast pipe for >>> transmitting ftrace data to a Host PC for further analysis. >>> >>> Note that in order to decode the data, one needs access to kernel >>> symbols in order to convert binary data into function names and what >>> not. >>> >>> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> >>> --- >>> >>> I wanted to take this through the gadget tree, but there is a >>> dependency with a previous patch of mine adding and extra argument to >>> the ->write() function. Hoping someone else will take it. >> >> just as an extra note here. In order for this to be really useful, it >> would be nice to be able to control what is going to be traced over USB > > Probably you will also need to export *atleast* symbol information. In future,
just keep your vmlinux around. This is not supposed to be shipped on end products, only debug builds.
> if this framework is extended to export tracepoint/kprobe/uprobe event data, > then the information like event format etc will also need to be exported. > > What tool do you use on host machine in order to extract information from this > exported target ring buffer data? > IMHO, standard tools like trace-cmd will not be able to use it as it is.
I hacked something together with libusb for testing. Proper tooling is needed, indeed.
-- balbi [unhandled content-type:application/pgp-signature]
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