Why is it different? Kubernetes Pod reporting more memory usage than actual process consumption

Question

Why does kubernetes memory usage seem higher?

I'm confused which metric is the real process's memory usage

1. kubernetes top pod

2. kubectl exec -it cm-gw-ts-skt-b4f5cd9bd-9mz66 -- jstat -gc pgrep java 1000 3| tail -n 3 | awk '{split($0,a," "); total=a[1]+a[2]+a[5]+a[7]; sum=a[3]+a[4]+a[6]+a[8]; print "used: " sum ", total: " total}'

3. top > 'ss'

please let me know the truth

/ # jstat -gc `pgrep java` 1000 3| tail -n 3 | awk '{split($0,a," "); total=a[1]+a[2]+a[5]+a[7]; sum=a[3]+a[4]+a[6]+a[8]; print "used: " sum ", total: " total}'
used: 316446, total: 1003648
used: 324332, total: 1003648
used: 328515, total: 1003648
/ # java -XX:+PrintFlagsFinal -version | grep -iE 'heapsize|permsize|threadstacksize'
     intx CompilerThreadStackSize                  = 1024                                   {pd product} {default}
   size_t ErgoHeapSizeLimit                        = 0                                         {product} {default}
   size_t HeapSizePerGCThread                      = 43620760                                  {product} {default}
   size_t InitialHeapSize                          = 1027604480                                {product} {ergonomic}
   size_t LargePageHeapSizeThreshold               = 134217728                                 {product} {default}
   size_t MaxHeapSize                              = 16418603008                               {product} {ergonomic}
   size_t MinHeapSize                              = 8388608                                   {product} {ergonomic}
    uintx NonNMethodCodeHeapSize                   = 5826188                                {pd product} {ergonomic}
    uintx NonProfiledCodeHeapSize                  = 122916026                              {pd product} {ergonomic}
    uintx ProfiledCodeHeapSize                     = 122916026                              {pd product} {ergonomic}
   size_t SoftMaxHeapSize                          = 16418603008                            {manageable} {ergonomic}
     intx ThreadStackSize                          = 1024                                   {pd product} {default}
     intx VMThreadStackSize                        = 1024                                   {pd product} {default}

I don't know what to do