RFR: 8268228: TSC is not used for CPUTimeStampCounter on AMD processor

[Yasumasa Suenaga]

I ran JVM on Ryzen 3300X, and I got following `jdk.CPUTimeStampCounter` event.


jdk.CPUTimeStampCounter {
  startTime = 10:41:14.993
  fastTimeEnabled = false
  fastTimeAutoEnabled = true
  osFrequency = 1000000000
  fastTimeFrequency = 1000000000
}


I confirmed 3300X supports Invariant TSC (so `fastTimeAutoEnabled` is set to `true`), however it does not seem to be used (`fastTimeEnabled` is `false`).

Frequency is come from brand string from CPUID (e.g. "Intel(R) Core(TM) i3-8145U CPU @ 2.10GHz"). However AMD processor (Ryzen at least) does not have it ("AMD Ryzen 3 3300X 4-Core Processor").
Fortunately rdtsc_x86.cpp can calculate the frequency like bogomips. We should fallback to it if we cannot get the frequency even if invariant TSC is supported.

After this change, I got following `jdk.CPUTimeStampCounter` event. Base clock of Ryzen 3 3300X is 3.8GHz, so `fastTimeFrequency` looks good.


jdk.CPUTimeStampCounter {
  startTime = 10:33:52.884
  fastTimeEnabled = true
  fastTimeAutoEnabled = true
  osFrequency = 10000000 Hz
  fastTimeFrequency = 3792929124 Hz
}


This problem is not only for JFR. I confirmed `Rdtsc` class is used in ticks.cpp , and it relates to GC code at least.

-------------

Commit messages:
 - 8268228: TSC is not used on AMD processor

Changes: https://git.openjdk.java.net/jdk/pull/4350/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4350&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268228
  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4350.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4350/head:pull/4350

PR: https://git.openjdk.java.net/jdk/pull/4350