On 10/15/2012 10:53 PM, Arun Sharma wrote: > On 10/15/12 8:55 AM, Robert Richter wrote: > > [..] >> Perf tool works then out-of-the-box with: >> >> $ perf record -e cpu/stalled-cycles-fixed-point/ ... >> >> The event string can easily be reused by other architectures as a >> quasi standard. > > I like Robert's proposal better. It's hard to model all the stall events > (eg: instruction decoder related stalls on x86) in a hardware > independent way. > > Another area to think about: software engineers are generally busy and > have a limited amount of time to devote to hardware event based > optimizations. The most common question I hear is: what is the expected > perf gain if I fix this? It's hard to answer that with just the stall > events. >
Hardware event based optimization is a very important aspect of real world application tuning. CPI stack analysis is a good reason why perf should have stall events as generic ones. But I am not clear on situations where we consider adding these new generic events into linux/perf_event.h and the situations where we should go with the sys fs interface. Could you please elaborate on this ? Regards Anshuman -- 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/
