[libcamera-devel] [PATCH] libcamera: Improve Request life cycle tracking

[Niklas Söderlund]

Hi Jacopo,

Thanks for your bikeshedding opportunity :-)

On 2021-01-28 10:04:54 +0100, Jacopo Mondi wrote:
> The current logging to track the status of a Request when running the
> Android camera HAL provide the following information:
> 
> When a Request is queued to libcamera:
> HAL camera_device.cpp:1776 '\_SB_.PCI0.I2C2.CAM0': Queueing Request to libcamera with 1 HAL streams
> 
> When a Request completes:
> Request request.cpp:268 Request has completed - cookie: 138508601719648
> 
> The queueing of a Request reports the number of streams it contains
> while the completion of a Request reports the address of the associated
> cookie.
> 
> This makes very hard to keep track of what Requests have completed, as
> the logging associated with a queue/complete event does not allow to identify
> a Request easily.
> 
> Add two more printouts to make it easier to track a Request life cycle.
> 
> The result looks like the following trace:
> 

I like the improvement, but I would alter it slightly. I think having 
the cookie value is the real value here as it makes it possible to trace 
a request.

> Request request.cpp:92 Created request - cookie: 138508601718368
> HAL camera_device.cpp:1776 '\_SB_.PCI0.I2C2.CAM0': Queueing Request to libcamera with 1 HAL streams

I would remove this print to increase signal to noise. If the number of 
streams really are important I would do a 1/n thing on the line below.  
If the line is keept I would also print the cookie.

> HAL camera_device.cpp:1813 '\_SB_.PCI0.I2C2.CAM0': 0 - (640x480)[0x00000022] -> (640x480)[NV12] (direct)

I would add the cookie.

> ...
> ...
> Request request.cpp:268 Request has completed - cookie: 138508601718368
> HAL camera_device.cpp:1866 '\_SB_.PCI0.I2C2.CAM0': Request completed by libcamera with 1 streams

I would add the cookie and possibly s/with 1 streams//

Bikeshedding is fun but take only what you like. At the end if all lines 
have the cookie you can also take my,

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/android/camera_device.cpp | 3 +++
>  src/libcamera/request.cpp     | 2 ++
>  2 files changed, 5 insertions(+)
> 
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index a9634f4e4198..513f000b1854 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -1863,6 +1863,9 @@ void CameraDevice::requestComplete(Request *request)
>  		status = CAMERA3_BUFFER_STATUS_ERROR;
>  	}
>  
> +	LOG(HAL, Debug) << "Request completed by libcamera with "
> +			<< descriptor->numBuffers_ << " streams";
> +
>  	/*
>  	 * \todo The timestamp used for the metadata is currently always taken
>  	 * from the first buffer (which may be the first stream) in the Request.
> diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
> index a68684ef9fd3..e561ce1d5d0e 100644
> --- a/src/libcamera/request.cpp
> +++ b/src/libcamera/request.cpp
> @@ -88,6 +88,8 @@ Request::Request(Camera *camera, uint64_t cookie)
>  	metadata_ = new ControlList(controls::controls);
>  
>  	LIBCAMERA_TRACEPOINT(request_construct, this);
> +
> +	LOG(Request, Debug) << "Created request - cookie: " << cookie_;
>  }
>  
>  Request::~Request()
> -- 
> 2.30.0
> 
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-- 
Regards,
Niklas Söderlund