a671d614ca
Iprobe is an alpha-only system profiling suite which I'm porting from Linux/alpha to FreeBSD. Iprobe works by using the hardware profiling support built into alpha cpus. In a nutshell, what Iprobe does is to setup the alpha performance counters to sample the pc at a fairly high rate & dumps those pc samples out to user space. Then some code runs to map the sampled PCs to functions. You get a bit more than that (like the PSL word, so you can tell if you're in the kernel or userland, what the ipl is, etc).