Try to fill darwin arm64 from sysctl (#105)

* fill CPUInfo on darwin arm64

go.mod

@@ -1,3 +1,5 @@
 module github.com/klauspost/cpuid/v2
 
 go 1.15
+
+require golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e h1:CsOuNlbOuf0mzxJIefr6Q4uAUetRUwZE4qt7VfzP+xo=
+golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

os_darwin_arm64.go

@@ -2,18 +2,120 @@
 
 package cpuid
 
-import "runtime"
+import (
+	"runtime"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
 
 func detectOS(c *CPUInfo) bool {
+	if runtime.GOOS != "ios" {
+		tryToFillCPUInfoFomSysctl(c)
+	}
 	// There are no hw.optional sysctl values for the below features on Mac OS 11.0
 	// to detect their supported state dynamically. Assume the CPU features that
 	// Apple Silicon M1 supports to be available as a minimal set of features
 	// to all Go programs running on darwin/arm64.
 	// TODO: Add more if we know them.
 	c.featureSet.setIf(runtime.GOOS != "ios", AESARM, PMULL, SHA1, SHA2)
-	c.PhysicalCores = runtime.NumCPU()
-	// For now assuming 1 thread per core...
-	c.ThreadsPerCore = 1
-	c.LogicalCores = c.PhysicalCores
+
 	return true
 }
+
+func sysctlGetBool(name string) bool {
+	value, err := unix.SysctlUint32(name)
+	if err != nil {
+		return false
+	}
+	return value != 0
+}
+
+func sysctlGetString(name string) string {
+	value, err := unix.Sysctl(name)
+	if err != nil {
+		return ""
+	}
+	return value
+}
+
+func sysctlGetInt(unknown int, names ...string) int {
+	for _, name := range names {
+		value, err := unix.SysctlUint32(name)
+		if err != nil {
+			continue
+		}
+		if value != 0 {
+			return int(value)
+		}
+	}
+	return unknown
+}
+
+func sysctlGetInt64(unknown int, names ...string) int {
+	for _, name := range names {
+		value64, err := unix.SysctlUint64(name)
+		if err != nil {
+			continue
+		}
+		if int(value64) != unknown {
+			return int(value64)
+		}
+	}
+	return unknown
+}
+
+func setFeature(c *CPUInfo, name string, feature FeatureID) {
+	c.featureSet.setIf(sysctlGetBool(name), feature)
+}
+func tryToFillCPUInfoFomSysctl(c *CPUInfo) {
+	c.BrandName = sysctlGetString("machdep.cpu.brand_string")
+
+	if len(c.BrandName) != 0 {
+		c.VendorString = strings.Fields(c.BrandName)[0]
+	}
+
+	c.PhysicalCores = sysctlGetInt(runtime.NumCPU(), "hw.physicalcpu")
+	c.ThreadsPerCore = sysctlGetInt(1, "machdep.cpu.thread_count", "kern.num_threads") /
+		sysctlGetInt(1, "hw.physicalcpu")
+	c.LogicalCores = sysctlGetInt(runtime.NumCPU(), "machdep.cpu.core_count")
+	c.Family = sysctlGetInt(0, "machdep.cpu.family", "hw.cpufamily")
+	c.Model = sysctlGetInt(0, "machdep.cpu.model")
+	c.CacheLine = sysctlGetInt64(0, "hw.cachelinesize")
+	c.Cache.L1I = sysctlGetInt64(-1, "hw.l1icachesize")
+	c.Cache.L1D = sysctlGetInt64(-1, "hw.l1icachesize")
+	c.Cache.L2 = sysctlGetInt64(-1, "hw.l2cachesize")
+	c.Cache.L3 = sysctlGetInt64(-1, "hw.l3cachesize")
+
+	// from https://developer.arm.com/downloads/-/exploration-tools/feature-names-for-a-profile
+	setFeature(c, "hw.optional.arm.FEAT_AES", AESARM)
+	setFeature(c, "hw.optional.AdvSIMD", ASIMD)
+	setFeature(c, "hw.optional.arm.FEAT_DotProd", ASIMDDP)
+	setFeature(c, "hw.optional.arm.FEAT_RDM", ASIMDRDM)
+	setFeature(c, "hw.optional.FEAT_CRC32", CRC32)
+	setFeature(c, "hw.optional.arm.FEAT_DPB", DCPOP)
+	// setFeature(c, "", EVTSTRM)
+	setFeature(c, "hw.optional.arm.FEAT_FCMA", FCMA)
+	setFeature(c, "hw.optional.arm.FEAT_FP", FP)
+	setFeature(c, "hw.optional.arm.FEAT_FP16", FPHP)
+	setFeature(c, "hw.optional.arm.FEAT_PAuth", GPA)
+	setFeature(c, "hw.optional.arm.FEAT_JSCVT", JSCVT)
+	setFeature(c, "hw.optional.arm.FEAT_LRCPC", LRCPC)
+	setFeature(c, "hw.optional.arm.FEAT_PMULL", PMULL)
+	setFeature(c, "hw.optional.arm.FEAT_SHA1", SHA1)
+	setFeature(c, "hw.optional.arm.FEAT_SHA256", SHA2)
+	setFeature(c, "hw.optional.arm.FEAT_SHA3", SHA3)
+	setFeature(c, "hw.optional.arm.FEAT_SHA512", SHA512)
+	// setFeature(c, "", SM3)
+	// setFeature(c, "", SM4)
+	setFeature(c, "hw.optional.arm.FEAT_SVE", SVE)
+
+	// from empirical observation
+	setFeature(c, "hw.optional.AdvSIMD_HPFPCvt", ASIMDHP)
+	setFeature(c, "hw.optional.armv8_1_atomics", ATOMICS)
+	setFeature(c, "hw.optional.floatingpoint", FP)
+	setFeature(c, "hw.optional.armv8_2_sha3", SHA3)
+	setFeature(c, "hw.optional.armv8_2_sha512", SHA512)
+	setFeature(c, "hw.optional.armv8_3_compnum", FCMA)
+	setFeature(c, "hw.optional.armv8_crc32", CRC32)
+}