liburcu4-dbgsym 0.9.1-3 (amd64 binary) in ubuntu yakkety

 This data synchronization library provides read-side access which scales
 linearly with the number of cores. It does so by allowing multiples copies of
 a given data structure to live at the same time, and by monitoring the data
 structure accesses to detect grace periods after which memory reclamation is
 possible.