Re: [RFC PATCH 1/1] ALSA: virtio: trace control message lifecycles

[sashiko-bot@kernel.org]

> A timed-out control request can complete later or be canceled during
> teardown. The existing opcode-only timeout message does not identify the
> request or show when the queue gives it back, which makes it difficult to
> correlate control stalls with guest scheduling and device reset activity.
> 
> Add a virtio_snd_ctl_msg trace event with a per-send identifier and phases
> for enqueue, response, cancellation and the sender's wait outcome. Record
> PCM stream IDs where the request layout supplies one, the enqueue or wait
> result, and the device's used length and response status. Mark optional
> fields explicitly and check the writable response capacity before reading
> a status for the event.
> 
> Assign IDs only to requests sent while the event is enabled. Keep sender
> wait outcomes separate from queue completion so a timeout followed by a
> late response retains the same ID. Include neither audio data nor kernel
> addresses in the event.
> 
> Leave protocol results, request ownership and timeout handling unchanged.
> The added fields increase each control-message structure by 24 bytes on
> the tested ARM64 configurations, including when tracing is disabled. No
> events are added to PCM data completions.
> 
> Assisted-by: LLM
> Signed-off-by: Joonho Lee <mynameisjune111@gmail.com>

Sashiko has reviewed this patch and found no issues.

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