Various data bus monitoring, analysis, and logging systems, devices, and methods are described herein. In one example, an apparatus includes a first circuit configured to monitor first packets among traffic carried by one or more first directional lanes of a communication link established between a host and one or more endpoint devices and determine header information for the first packets. The apparatus includes a second circuit configured to detect second packets among traffic carried by one or more second directional lanes of the communication link based at least in part on the header information determined for the first packets. The apparatus includes an analysis element configured to establish transaction metadata comprising properties of transactions on the communication link based at least on correlations among the first packets and the second packets.