Messages in this thread | | | From | Cristian Marussi <> | Subject | [PATCH 0/2] Add SCMI full message tracing | Date | Thu, 23 Jun 2022 15:55:31 +0100 |
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Hi,
after a few recent troubles handling too strictly out-of-spec replies from SCMI servers deployed in the wild, I though it could have been useful to have a basic way to dump at will the effective full payloads of successfuly transmitted/received SCMI messages.
The existing SCMI traces already collect a bunch of information about SCMI message exchanges but they do NOT keep any payload information: this is certainly preferable most of the time since dumping full SCMI messages to the trace buffer involves a full copy of the payload.
For this reason I added a new distinct trace_scmi_msg_dump with this series in order to be able to selectively enable at will message dumping only when required.
Only successfully transmitted and received (valid) xfers are dumped.
At first I was thinking about just dumping raw header and payload, but in order to make the log a bit more human readable (without the need of tooling to parse the log), I added some parsing/interpretation of the header, so that the final result is something like:
root@deb-guest:~# echo 1 > /sys/kernel/debug/tracing/events/scmi/scmi_msg_dump/enable root@deb-guest:~# cat /sys/kernel/debug/tracing/trace_pipe
(my annotations non on traces =>>) proto type cmd seq status payload | | | | | | ++ cmd/reply | | | | | | cat-224 [002] ..... 147.755847: scmi_msg_dump: [0x15]:CMND:[0x06]:[0021]:[0]: 0000000000000000 <idle>-0 [000] d.h2. 147.758311: scmi_msg_dump: [0x15]:RESP:[0x06]:[0021]:[0]: 25000000000000000000000000000000
++ cmd/reply/delayed cat-223 [001] ..... 122.384192: scmi_msg_dump: [0x15]:CMND:[0x06]:[0020]:[0]: 0100000001000000 <idle>-0 [000] d.h2. 122.405548: scmi_msg_dump: [0x15]:RESP:[0x06]:[0020]:[0]: <idle>-0 [000] d.h2. 122.425839: scmi_msg_dump: [0x15]:DLYD:[0x06]:[0020]:[0]: 01000000a05a320000000000efbeaddefecafeca
++ enable notif/notif iio_generic_buf-233 [003] ..... 522.399690: scmi_msg_dump: [0x15]:CMND:[0x0A]:[0024]:[0]: 0800000003000000 <idle>-0 [000] dNh2. 522.417778: scmi_msg_dump: [0x15]:RESP:[0x0A]:[0024]:[0]: 00000000 <idle>-0 [000] d.h2. 522.500945: scmi_msg_dump: [0x15]:NOTI:[0x01]:[0000]:[0]: 000000000800000008daffffffffffff0040d3a45d46fb1610daffffffffffff0040d3a45d46fb1618daffffffffffff0040d3a45d46fb16
Payload is dumped as it comes through byte-by-byte without any endianity conversion to avoid further load on the system.
Any thoughs ?
Thanks, Cristian
Cristian Marussi (2): include: trace: Add SCMI full message tracing firmware: arm_scmi: Use new SCMI full message tracing
drivers/firmware/arm_scmi/driver.c | 21 ++++++++++++++++++++ include/trace/events/scmi.h | 31 ++++++++++++++++++++++++++++++ 2 files changed, 52 insertions(+)
-- 2.32.0
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