Re: [PATCH 0/4] firmware: arm_scmi: Add xfer inflight debug and trace

[Peng Fan]

On Fri, Jun 20, 2025 at 09:27:52AM +0000, Philip Radford wrote:
>
>
>> -----Original Message-----
>> From: Peng Fan <peng.fan@xxxxxxxxxxx>
>> Sent: Friday, June 20, 2025 9:47 AM
>> To: Philip Radford <Philip.Radford@xxxxxxx>
>
>Hi,
>Thanks for the review.
>
>> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; arm-
>> scmi@xxxxxxxxxxxxxxx; Sudeep Holla <Sudeep.Holla@xxxxxxx>; Cristian
>> Marussi <Cristian.Marussi@xxxxxxx>; Luke Parkin <Luke.Parkin@xxxxxxx>
>> Subject: Re: [PATCH 0/4] firmware: arm_scmi: Add xfer inflight debug and
>> trace
>> 
>> On Thu, Jun 19, 2025 at 12:20:00PM +0000, Philip Radford wrote:
>> >Hi all,
>> >
>> >This series adds a new counter to the Arm SCMI firmware driver to track
>> >the number of in-flight message transfers during debug and trace. This
>> >will be useful for examining behaviour under a large load with regards
>> >to concurrent messages being sent and received. As the counter only gives
>> >a live value, printing the value in trace allows logging of the in-flight
>> >xfers.
>> 
>> Just a general question, is this counter count in flight messages
>> for a scmi instance or it is per transport? I ask because
>> one scmi instance could have multiple mailboxes. If counting based
>> on scmi instance, it may not be that accurate.
>> 
>> Thanks,
>> Peng
>> 
>
>Yes, you are correct that the counter is per instance, as are the other counters.
>This would mean that if you have multiple channels you would see the total
>number of inflight xfers across all channels, limited to that instance.
>If the inflight counter is non-zero and something is wrong, it would not be
>apparent which channel had an issue, however this is the same for the other
>counters.
>
>I feel like this series is a helpful addition to the current counters, but what you
>have pointed out is something that could be reworked in a future series?

Sure. It is ok from my view, you could extend the driver in future.

Regards,
Peng

>
>Regards,
>Phil