Messages in this thread |  | | Subject | Re: [PATCH 1/2] include: trace: Add SCMI header with trace events | From | Lukasz Luba <> | Date | Tue, 17 Dec 2019 10:05:28 +0000 |
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Hello Jim,
On 12/16/19 10:15 PM, Jim Quinlan wrote: > From: Lukasz Luba <lukasz.luba@arm.com> > > + > +TRACE_EVENT(scmi_xfer_begin, > + TP_PROTO(u8 id, u8 protocol_id, u16 seq, bool poll), > + TP_ARGS(id, protocol_id, seq, poll), > + > + TP_STRUCT__entry( > + __field(u8, id) > + __field(u8, protocol_id) > + __field(u16, seq) > + __field(bool, poll) > + ), > + > + TP_fast_assign( > + __entry->id = id; > + __entry->protocol_id = protocol_id; > + __entry->seq = seq; > + __entry->poll = poll; > + ), > + > + TP_printk("id=%u protocol_id=%u seq=%u poll=%u", __entry->id, > + __entry->protocol_id, __entry->seq, __entry->poll) > +); > + > +TRACE_EVENT(scmi_xfer_end, > + TP_PROTO(u8 id, u8 protocol_id, u16 seq, u32 status), > + TP_ARGS(id, protocol_id, seq, status), > + > + TP_STRUCT__entry( > + __field(u8, id) > + __field(u8, protocol_id) > + __field(u16, seq) > + __field(u32, status) > + ), > + > + TP_fast_assign( > + __entry->id = id; > + __entry->protocol_id = protocol_id; > + __entry->seq = seq; > + __entry->status = status; > + ), > + > + TP_printk("id=%u protocol_id=%u seq=%u status=%u", __entry->id, > + __entry->protocol_id, __entry->seq, __entry->status) > +); > > Hello, > > When there are multiple messages in the mbox queue, I've found it > a chore matching up the 'begin' event with the 'end' event for each > SCMI msg. The id (command) may not be unique, the proto_id may not be > unique, and the seq may not be unique. The combination of the three > may not be unique. Would it make sense to assign a monotonically > increasing ID to each msg so that one can easily match the two events > for each msg? This id could be the result of an atomic increment and > could be stored in the xfer structure. Of course, it would be one of > the values printed out in the events.
Hmmm, an atomic variable in this code might be too heavy, especially in case of fast_switch from cpufreq. Let me think about it and experiment.
> > Also, would you consider a third event, right after the > scmi_fetch_response() invocation in scmi_rx_callback()? I've found > this to be insightful in situations where we were debugging a timeout.
Yes, of course. It would be really useful. Thank you for the suggestion.
> > I'm fine if you elect not to do the above; I just wanted to post > this for your consideration.
Thant's a valuable feedback. I will definitely consider it.
Regards, Lukasz
> > Thanks, > Jim Quinlan > Broadcom >
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