Hi Thomas, On Mon, Jan 24, 2011 at 5:04 PM, Thomas Renninger <trenn@xxxxxxx> wrote: > Hi, > > as I recently cleaned up the power events with > some format/abi adjustings... > > I realized that it was rather easy to adjust > the stuff in drivers/tools/perf, because there > are some nice facilities to query which events > are available. > > I looked at pytimechart, there it's not that nice > and convenient would be some kind of version number. > > pytimechart can parse traces which are simply copied > away from /sys/kernel/debug/trace and to check for > available events and their format, one would have to > do a separate, ugly to implement, iteration of parsing. > > Would it make sense to introduce a trace > ABI version number? > It would be enough to increase it by one every time > any event (don't know about other perf facilities) is > added, removed or modified. > Ideally the modifications are tracked with a short > description in a file like Documentation/trace/format.changes > > Untested, but the patch at the end should simply add > a version number on top of > /sys/kernel/debug/trace file If needed the ABI versioning should at least contain a major and minor number, i.e. 'x.y'. The big question IMO is if it is needed or not. Is this a real problem in the userland? Are the apps always fitting the kernel ABI in a packaged distro? > > While this should be enough for the kernel, perf record > would need to include it into it's binary perf.data format > as well? > > Then userspace apps could easily test whether supported > events would be included at all, whether only a subset of > supported events were made available and which format they have. > > Does this make sense? > > Thanks, > > Thomas > Regards, Jean -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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