From d6bc98fc5a39e7ff16dc563408b35767024b13b5 Mon Sep 17 00:00:00 2001
From: xh4n3 <xyn1016@gmail.com>
Date: Fri, 5 Mar 2021 12:38:05 +0800
Subject: [PATCH] fix wrong NumCPU in kube-proxy under static CPU policy

Signed-off-by: xh4n3 <xyn1016@gmail.com>
---
 cmd/kube-proxy/app/server.go         |  3 +--
 cmd/kube-proxy/app/server_others.go  | 12 ++++++++++++
 cmd/kube-proxy/app/server_windows.go |  5 +++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/cmd/kube-proxy/app/server.go b/cmd/kube-proxy/app/server.go
index 75577d07f20..2d5ca952c31 100644
--- a/cmd/kube-proxy/app/server.go
+++ b/cmd/kube-proxy/app/server.go
@@ -24,7 +24,6 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
-	goruntime "runtime"
 	"strings"
 	"time"
 
@@ -784,7 +783,7 @@ func getConntrackMax(config kubeproxyconfig.KubeProxyConntrackConfiguration) (in
 		if config.Min != nil {
 			floor = int(*config.Min)
 		}
-		scaled := int(*config.MaxPerCore) * goruntime.NumCPU()
+		scaled := int(*config.MaxPerCore) * detectNumCPU()
 		if scaled > floor {
 			klog.V(3).Infof("getConntrackMax: using scaled conntrack-max-per-core")
 			return scaled, nil
diff --git a/cmd/kube-proxy/app/server_others.go b/cmd/kube-proxy/app/server_others.go
index bcbf7392f06..62547325b34 100644
--- a/cmd/kube-proxy/app/server_others.go
+++ b/cmd/kube-proxy/app/server_others.go
@@ -25,9 +25,12 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	goruntime "runtime"
 	"strings"
 	"time"
 
+	"github.com/google/cadvisor/machine"
+	"github.com/google/cadvisor/utils/sysfs"
 	"k8s.io/apimachinery/pkg/watch"
 
 	"k8s.io/apimachinery/pkg/runtime"
@@ -436,6 +439,15 @@ func detectNodeIP(client clientset.Interface, hostname, bindAddress string) net.
 	return nodeIP
 }
 
+func detectNumCPU() int {
+	// try get numCPU from /sys firstly due to a known issue (https://github.com/kubernetes/kubernetes/issues/99225)
+	_, numCPU, err := machine.GetTopology(sysfs.NewRealSysFs())
+	if err != nil || numCPU < 1 {
+		return goruntime.NumCPU()
+	}
+	return numCPU
+}
+
 func getDetectLocalMode(config *proxyconfigapi.KubeProxyConfiguration) (proxyconfigapi.LocalMode, error) {
 	mode := config.DetectLocalMode
 	switch mode {
diff --git a/cmd/kube-proxy/app/server_windows.go b/cmd/kube-proxy/app/server_windows.go
index abc15173558..12c714a3934 100644
--- a/cmd/kube-proxy/app/server_windows.go
+++ b/cmd/kube-proxy/app/server_windows.go
@@ -24,6 +24,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	goruntime "runtime"
 
 	// Enable pprof HTTP handlers.
 	_ "net/http/pprof"
@@ -185,6 +186,10 @@ func getProxyMode(proxyMode string, kcompat winkernel.KernelCompatTester) string
 	return proxyModeUserspace
 }
 
+func detectNumCPU() int {
+	return goruntime.NumCPU()
+}
+
 func tryWinKernelSpaceProxy(kcompat winkernel.KernelCompatTester) string {
 	// Check for Windows Kernel Version if we can support Kernel Space proxy
 	// Check for Windows Version