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

[Niklas Söderlund]

Hi Jacopo,

On 2021-02-01 11:36:48 +0100, Jacopo Mondi wrote:
> Hi Niklas,
> 
> On Sat, Jan 30, 2021 at 12:26:39AM +0100, Niklas Söderlund wrote:
> > 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.
> 
> I'm sorry I didn't fully get this one. What do you mean with "a 1/n
> thing on the line below" ?
> 
> Also, I think identifying how many streams the request contains is
> relevant.

I was thinking of if it make sens to instead of

  HAL camera_device.cpp:1776 '\_SB_.PCI0.I2C2.CAM0': Queueing Request to libcamera with 2 HAL streams
  HAL camera_device.cpp:1813 '\_SB_.PCI0.I2C2.CAM0': 0 - 640x480)[0x00000022] -> (640x480)[NV12] (direct)
  HAL camera_device.cpp:1813 '\_SB_.PCI0.I2C2.CAM0': 1 - 640x480)[0x00000022] -> (640x480)[NV12] (direct)

Have something like,

  HAL camera_device.cpp:1813 '\_SB_.PCI0.I2C2.CAM0': cookie: 138508601718368 stream: 1/2 - 640x480)[0x00000022] -> (640x480)[NV12] (direct)
  HAL camera_device.cpp:1813 '\_SB_.PCI0.I2C2.CAM0': cookie: 138508601718368 stream: 2/2 - 640x480)[0x00000022] -> (640x480)[NV12] (direct)

I find the later more compact while at the same time providing more 
information in a situation where you have to debug from a log file.

> 
> >
> > > 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//
> 
> If we remove the stream count and add the cookie, I would then rather
> drop the printout in camera_device.cpp completely, as it will provide
> the exact same information that the one in request.cpp provides...

Is it a problem that the same information is printed at different 
levels? I like to see such things as it allows me to from a log file 
track how a request moved thru the layers. Also if I'm only interested 
in debugging a specific component maybe I have a 
LIBCAMERA_LOG_LEVELS=HAL:0 or such set?

In either case as stated in my first reply this is all bikeshedding so I 
don't feel strongly about any of it :-)

> 
> >
> > 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
> > >
> > > _______________________________________________
> > > libcamera-devel mailing list
> > > libcamera-devel at lists.libcamera.org
> > > https://lists.libcamera.org/listinfo/libcamera-devel
> >
> > --
> > Regards,
> > Niklas Söderlund

-- 
Regards,
Niklas Söderlund