Index: cpu.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/cpu.c,v
retrieving revision 1.152
diff -u -p -r1.152 cpu.c
--- cpu.c	28 Nov 2020 18:40:01 -0000	1.152
+++ cpu.c	29 Dec 2020 12:25:15 -0000
@@ -69,6 +69,7 @@
 #include "vmm.h"
 #include "pctr.h"
 #include "pvbus.h"
+#include "kstat.h"
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -113,6 +114,10 @@
 #include <dev/pv/pvvar.h>
 #endif
 
+#if NKSTAT > 0
+#include <sys/kstat.h>
+#endif
+
 #include <dev/ic/mc146818reg.h>
 #include <amd64/isa/nvram.h>
 #include <dev/isa/isareg.h>
@@ -686,6 +691,61 @@ replacexsave(void)
 	splx(s);
 }
 
+#if NKSTAT > 0
+struct cpu_perf_kstat {
+	struct kstat_kv		kp_tsc;
+	struct kstat_kv		kp_mperf;
+	struct kstat_kv		kp_aperf;
+};
+
+int
+cpu_perf_read(struct kstat *ks)
+{
+	struct cpu_perf_kstat *kp = ks->ks_data;
+	unsigned long s;
+
+	s = intr_disable();
+	kstat_kv_u64(&kp->kp_tsc) = rdtsc();
+	kstat_kv_u64(&kp->kp_mperf) = rdmsr(0xe7);
+	kstat_kv_u64(&kp->kp_aperf) = rdmsr(0xe8);
+	intr_restore(s);
+
+	nanouptime(&ks->ks_updated);
+
+	return (0);
+}
+
+void
+cpu_init_kstat(struct cpu_info *ci)
+{
+	struct kstat *ks;
+	struct cpu_perf_kstat *kp;
+
+	ks = kstat_create("cpu", CPU_INFO_UNIT(ci), "perf", 0, KSTAT_T_KV, 0);
+	if (ks == NULL) {
+		printf("%s: unable to create kstats\n", ci->ci_dev->dv_xname);
+		return;
+	}
+
+	kstat_set_cpu(ks, ci);
+
+	kp = malloc(sizeof(*kp), M_DEVBUF, M_WAITOK|M_ZERO);
+
+	kstat_kv_unit_init(&kp->kp_tsc, "tsc",
+	    KSTAT_KV_T_COUNTER64, KSTAT_KV_U_CYCLES);
+	kstat_kv_unit_init(&kp->kp_mperf, "mperf",
+	    KSTAT_KV_T_COUNTER64, KSTAT_KV_U_CYCLES);
+	kstat_kv_unit_init(&kp->kp_aperf, "aperf",
+	    KSTAT_KV_T_COUNTER64, KSTAT_KV_U_CYCLES);
+
+	ks->ks_data = kp;
+	ks->ks_datalen = sizeof(*kp);
+	ks->ks_read = cpu_perf_read;
+
+	//ci->ci_kstat = ks;
+	kstat_install(ks);
+}
+#endif /* NKSTAT > 0 */
 
 /*
  * Initialize the processor appropriately.
@@ -808,6 +868,10 @@ cpu_boot_secondary_processors(void)
 			continue;
 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
 			continue;
+#if NKSTAT > 0
+		/* this is a convenient place to do this */
+		cpu_init_kstat(ci);
+#endif
 		if (ci->ci_flags & (CPUF_BSP | CPUF_SP | CPUF_PRIMARY))
 			continue;
 		ci->ci_randseed = (arc4random() & 0x7fffffff) + 1;