On Tue, Sep 02, 2014 at 02:18:16PM -0600, Mathieu Poirier wrote: > Pawell, many thanks for looping me in. > > I am definitely not a perf-internal guru and as such won't be able to > comment on the implementation. On the flip side it is easy for me to see > how the work on coresight done at Linaro can be made to tie-in what > Alexander is proposing. Albeit not at the top of the priority list at this > time, integration with perf (and ftrace) is definitely on the roadmap. > > Powell is correct in his statement that Linaro's work in HW trace decoding > is (currently) mainly focused on processor tracing but that will change > when we have the basic infrastructure upstreamed. > > Last but not least it would be interesting to have more information on the > "sideband data". With coresight we have something called "metadata", also > related to how the trace source was configured and instrumental to proper > trace decoding. I'm pretty sure we are facing the same problems.
So we use the sideband or AUX data stream to export the 'big' data stream generated by the CPU in an opaque manner. For every AUX data block 'posted' we issue an event into the regular data buffer that describes it. I was assuming that both ARM and MIPS would generate a single data stream as well. So please do tell more about your meta-data; is that a one time thing or a second continuous stream of data, albeit smaller than the main stream? The way I read your explanation it is a one time blob generated once you setup the hardware. I suppose we could either dump it once into the normal data stream or maybe dump it once every time we generate an AUX buffer event into the normal data stream -- if its not too big. In any case, can you point us to public documentation of the ARM CoreSight stuff and maybe provide a short summary for the tl;dr crowd? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
