util: add affinity-cpus starting argument (#10773)

go.mod

@@ -68,7 +68,7 @@ require (
 	go.uber.org/atomic v1.3.2
 	go.uber.org/zap v1.9.1
 	golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e
-	golang.org/x/sys v0.0.0-20190109145017-48ac38b7c8cb // indirect
+	golang.org/x/sys v0.0.0-20190109145017-48ac38b7c8cb
 	golang.org/x/text v0.3.0
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4 // indirect
 	golang.org/x/tools v0.0.0-20190130214255-bb1329dc71a0

tidb-server/main.go

@@ -20,6 +20,7 @@ import (
 	"os"
 	"runtime"
 	"strconv"
+	"strings"
 	"sync/atomic"
 	"time"
 
@@ -53,6 +54,7 @@ import (
 	"github.com/pingcap/tidb/util/memory"
 	"github.com/pingcap/tidb/util/printer"
 	"github.com/pingcap/tidb/util/signal"
+	"github.com/pingcap/tidb/util/sys/linux"
 	"github.com/pingcap/tidb/util/systimemon"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/push"
@@ -90,6 +92,7 @@ const (
 
 	nmProxyProtocolNetworks      = "proxy-protocol-networks"
 	nmProxyProtocolHeaderTimeout = "proxy-protocol-header-timeout"
+	nmAffinityCPU                = "affinity-cpus"
 )
 
 var (
@@ -112,6 +115,7 @@ var (
 	tokenLimit       = flag.Int(nmTokenLimit, 1000, "the limit of concurrent executed sessions")
 	pluginDir        = flag.String(nmPluginDir, "/data/deploy/plugin", "the folder that hold plugin")
 	pluginLoad       = flag.String(nmPluginLoad, "", "wait load plugin name(separated by comma)")
+	affinityCPU      = flag.String(nmAffinityCPU, "", "affinity cpu (cpu-no. separated by comma, e.g. 1,2,3)")
 
 	// Log
 	logLevel     = flag.String(nmLogLevel, "info", "log level: info, debug, warn, error, fatal")
@@ -157,6 +161,7 @@ func main() {
 		os.Exit(0)
 	}
 	setGlobalVars()
+	setCPUAffinity()
 	setupLog()
 	// If configStrict had been specified, and there had been an error, the server would already
 	// have exited by now. If configWarning is not an empty string, write it to the log now that
@@ -184,6 +189,30 @@ func exit() {
 	os.Exit(0)
 }
 
+func setCPUAffinity() {
+	if affinityCPU == nil || len(*affinityCPU) == 0 {
+		return
+	}
+	var cpu []int
+	for _, af := range strings.Split(*affinityCPU, ",") {
+		af = strings.TrimSpace(af)
+		if len(af) > 0 {
+			c, err := strconv.Atoi(af)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "wrong affinity cpu config: %s", *affinityCPU)
+				exit()
+			}
+			cpu = append(cpu, c)
+		}
+	}
+	err := linux.SetAffinity(cpu)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "set cpu affinity failure: %v", err)
+		exit()
+	}
+	runtime.GOMAXPROCS(len(cpu))
+}
+
 func registerStores() {
 	err := kvstore.Register("tikv", tikv.Driver{})
 	terror.MustNil(err)
@@ -331,9 +360,6 @@ func reloadConfig(nc, c *config.Config) {
 	// like config.GetGlobalConfig().OOMAction.
 	// These config items will become available naturally after the global config pointer
 	// is updated in function ReloadGlobalConfig.
-	if nc.Performance.MaxProcs != c.Performance.MaxProcs {
-		runtime.GOMAXPROCS(int(nc.Performance.MaxProcs))
-	}
 	if nc.Performance.MaxMemory != c.Performance.MaxMemory {
 		plannercore.PreparedPlanCacheMaxMemory.Store(nc.Performance.MaxMemory)
 	}

util/sys/linux/sys_linux.go

@@ -14,7 +14,10 @@
 
 package linux
 
-import "syscall"
+import (
+	"golang.org/x/sys/unix"
+	"syscall"
+)
 
 // OSVersion returns version info of operation system.
 // e.g. Linux 4.15.0-45-generic.x86_64
@@ -38,3 +41,13 @@ func OSVersion() (osVersion string, err error) {
 	osVersion = charsToString(un.Sysname[:]) + " " + charsToString(un.Release[:]) + "." + charsToString(un.Machine[:])
 	return
 }
+
+// SetAffinity sets cpu affinity.
+func SetAffinity(cpus []int) error {
+	var cpuSet unix.CPUSet
+	cpuSet.Zero()
+	for _, c := range cpus {
+		cpuSet.Set(c)
+	}
+	return unix.SchedSetaffinity(unix.Getpid(), &cpuSet)
+}

util/sys/linux/sys_other.go

@@ -22,3 +22,8 @@ func OSVersion() (osVersion string, err error) {
 	osVersion = runtime.GOOS + "." + runtime.GOARCH
 	return
 }
+
+// SetAffinity sets cpu affinity.
+func SetAffinity(cpus []int) error {
+	return nil
+}