[ros-users] Nodelet version of rosbag?

Brian Gerkey gerkey at willowgarage.com
Sun Jan 30 20:21:39 UTC 2011


On Sun, Jan 30, 2011 at 11:47 AM, Radu Bogdan Rusu
<rusu at willowgarage.com> wrote:
> We could try creating a BAGWriter class similar to pcl_ros::BAGReader if you think that's useful. Basically you want to
> dump data to disk faster, without going through serialization/deserialization, right?

I'm pretty sure that rosbag doesn't deserialize anything, but rather
just dumps serialized messages to disk as fast as it can.   And
because the .bag format is serialized messages, you can't avoid the
serialization step.  I think that the nodelet method would only save
the (kernel-mediated) copy of each serialized message from the
producing node to rosbag.  From the point of view of throughput, I
would expect writing to disk to be the rate-limiting step.   I guess
it comes down to whether the CPU usage involved the node->rosbag copy
is significant.

	brian.

> On 01/30/2011 11:31 AM, Patrick Bouffard wrote:
>> Are there any plans to implement rosbag (in particular, rosbag record)
>> as a nodelet? I can see this being useful when you want to record
>> large amounts of camera or point cloud data.



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