Re: [PATCH RESEND 0/4] Add support for HiSilicon PCIe Tune and Trace device

[Alexander Shishkin]

Yicong Yang <yangyicong@xxxxxxxxxxxxx> writes:

> The reason for not using perf is because there is no current support
> for uncore tracing in the perf facilities.

Not unless you count

$ perf list|grep -ic uncore
77

> We have our own format
> of data and don't need perf doing the parsing.

Perf has AUX buffers, which are used for all kinds of own formats.

> A similar approach for implementing this function is ETM, which use
> sysfs for configuring and a character device for dumping data.

And also perf. One reason ETM has a sysfs interface is because the
driver predates perf's AUX buffers. Can't say if it's the only
reason. I'm assuming you're talking about Coresight ETM.

> Greg has some comments on our implementation and doesn't advocate
> to build driver on debugfs [1]. So I resend this series to
> collect more feedbacks on the implementation of this driver.
>
> Hi perf and ETM related experts, is it suggested to adapt this driver
> to perf? Or is the debugfs approach acceptable? Otherwise use

Aside from the above, I don't think the use of debugfs for kernel ABIs
is ever encouraged.

Regards,
--
Ale