> The whole point of the rdpmc() implementation is to be low overhead. > If you have to parse 10 different mmap() fields it starts to defeat the > purpose.
You would only use it with ref-cycles of course. So for the normal case there is no overhead. > If the watchdog counter is constantly running, can't you just modify > perf_event to just grab start/stop values at context switch time and > provide the difference to the user? Sort of like the "always running" > patchsets that float around? Though I guess that doesn't help much with > sampling. This wouldn't work with ring filters unfortunately. -Andi
