C.1. GFS2 tracepoint Types
The tracepoints are designed to be as generic as possible. This should mean that it will not be necessary to change the API during the course of Red Hat Enterprise Linux 6. On the other hand, users of this interface should be aware that this is a debugging interface and not part of the normal Red Hat Enterprise Linux 6 API set, and as such Red Hat makes no guarantees that changes in the GFS2 tracepoints interface will not occur.
Tracepoints are a generic feature of Red Hat Enterprise Linux 6 and their scope goes well beyond GFS2. In particular they are used to implement the
blktrace infrastructure and the
blktrace tracepoints can be used in combination with those of GFS2 to gain a fuller picture of the system performance. Due to the level at which the tracepoints operate, they can produce large volumes of data in a very short period of time. They are designed to put a minimum load on the system when they are enabled, but it is inevitable that they will have some effect. Filtering events with a variety of means can help reduce the volume of data and help focus on obtaining just the information which is useful for understanding any particular situation.