NEWHPROF: gethrvtime()/gettimeofday() vs JVMTI GetCurrentThreadCpuTime()

On Solaris, newhprof is using high res timer and gethrvtime().
On Linux, it's using gettimeofday().
On Windows, GetTime()?

If I use the JVMTI GetThreadCpuTime() the performance suffers.
Recent changes in HotSpot seem to have changed the old 1.4.2 behavior
of get_thread_cpu_time, making it much slower but more accurate.

The number of times this is called with cpu=times in newhprof (and old
hprof for that matter) makes it critical that it be fast.