LinuxCon + CloudOpen + ELC-E Europe 2014

Because mainframes traditionally run mission critical workloads, serviceability has always been of high importance to the platform. Customers expect that the root cause of a problem can be found with the first set of debug data that is collected. Reproducing the error is not welcome and must be avoided. With this in mind, IBM provided the s390dbf kernel tracing infrastructure when Linux was ported to the s390 architecture at the beginning of 2000. This was about eight years before Linux ftrace and tracepoints were integrated into the upstream Linux kernel. In some areas, tracepoints offer advantages, for example, per-CPU trace buffers or an event streaming capability. Yet, tracepoints do not offer all features that are needed for s390. This presentation reviews the two tracing features and shows what would have to be added to tracepoints to achieve the same functionality as s390dbf.