On Fri, 20 Aug 2010, stephane eranian wrote: > > However I have one comment: > > The event table has the encoding that is specific to perf_events. This > means > the table can only be used with perf_events. That is not the approach taken > by libpfm4. I am trying hard to make the core of the library OS-agnostic. > That > means the table should have the official encodings of the event. If you > need > an OS specific encoding, then you need to add a shim layer specific to the > OS > to make the conversion.
at least for the Cortex A8 (the machine I have) the perf events match the actual value you set to hardware (with the difference that it's only a 32-bit hardware register). For example, in the Cortex-A8 Technical Reference manual, section 3.2.50 it shows that the EVTSEL (EVent SELection) register is just a 32-bit value with the lowest 8-bits being the "EVTSEL" bits (and the other bits are reserverd). The event values in table 3-98 correspond exactly to the 8-bit value used by perf events. There are a few possible corner cases; most notably I think perf-events might play some tricks to get the cycle count (which is provided by a separate register, I'll have to check on that). Now the other ARM chips might be different, I have to admit that I haven't tracked down the documentation for them yet. But at least for the chip I have the perf events values match the actual hardware register values. Vince ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
