Interprocess publishing slowing down nodelets ?

edit

Hi,

I have a node composed of nodelets that does image processing. I use nodelets in order to avoid the overhead of interprocess image transfers which helps a lot. However, while I only use image data within my node (in another nodelet), I'd like to record my image stream in a bag file. This, unfortunately, seems to slow down the node as a whole.

I suspect that this is due to the interprocess image publishing somehow clogging up the node's ROS worker threads, but as I don't know much about how ROS works at a lower level this is a complete guess on my part.

My question is : is my intuition correct, and is there a way to make it so that interprocess publishing won't slow down the publishing node ?

Since publishing is asynchronous I'd imagine throwing another thread in the mix could maybe solve the issue.

Thanks !