An alternative in getting CPU freq on M-series

This solution was retrieved from
https://listman.redhat.com/archives/libvir-list/2022-February/228217.html
sysctl hw.cpufrequency would result as empty on Apple Silicon (at least) M1,
when run natively. Ironically (and that's why it's been working with viewers
relying on Rosetta 2), arch -x86_64 /bin/bash -c 'sysctl hw.cpufrequency'
run on an Apple Silicon would result in the correct number.

indra/llcommon/llprocessor.cpp

@@ -637,7 +637,15 @@ public:
     LLProcessorInfoDarwinImpl()
     {
         getCPUIDInfo();
+#ifdef __arm64__
+        auto frequency = getSysctlInt64("hw.tbfrequency");
+        struct clockinfo clockrate;
+        auto clockrate_len = sizeof(clockrate);
+        if (!sysctlbyname("kern.clockrate", &clockrate, &clockrate_len, NULL, 0))
+            frequency *= clockrate.hz;
+#else
         uint64_t frequency = getSysctlInt64("hw.cpufrequency");
+#endif
         setInfo(eFrequency, (F64)frequency  / (F64)1000000);
     }