On Fri, Dec 23, 2011 at 01:16:41PM -0500, Mathieu Desnoyers wrote: > > (note that ABI to control the tracer and ABI to transport data could > share the same version numbering if the control tools and transport > tools happen to reside in the same user-level packages) Being able to control the tracer but then not being able to look at the trace output is useless. So they might as well be the same thing.... > - The trace data format > - Both versioned _and_ self-described. > Self-description of the event/field layout allows the same tools to > understand traces gathered on different kernel versions, on different > architectures, with different tracer configurations. > Versioning on top of the self-described trace format allows changes > to what the trace self-description can express. So there are two ways to do this. One is to make changes be backwards compatible, so that the trace data format only breaks if you use the new feature; if it doesn't you encode things the old fashioned way. The other way of doing things is to randomly break users whenever the tracing developers decide to add some random new feature, regardless of whether or not a partiuclar user finds that new feature to be useful. The first is acceptable. The second, IMHO, is not. Linus has said quite strongly that WE DO NOT BREAK USERSPACE. Period. Regards, - Ted _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
