Readdir rm -rf graphs

From Linux NFS

    36: Linux 2.6.36
36NORC: Linux 2.6.36 (without readdir cap)
    38: Linux 2.6.38
  38RC: Linux 2.6.38 (with readdir cap added back)
  38NB: Linux 2.6.38 (with Neil Brown's patch and loop detection)

Contents 1 Real 1.1 NFS v3 1.2 NFS v4 2 Sys 2.1 NFS v3 2.2 NFS v4 3 RPC ops 3.1 NFS v3 3.2 NFS v4

Real

NFS v3

• 
  • Without readdir plus, an unmodified 2.6.38 kernel takes longer to remove a large directory than the other kernels
• 
  • Using readdir plus removes large directories faster than using a simple readdir.

NFS v4

• 
  • Kernels perform the same without readdir plus
• 
  • With readdir plus enabled, the kernels take about the same amount of time to remove the directory.

Sys

NFS v3

• 
  • The command takes about the same amount of kernel time for each tested kernel.
• 
• Using readdir plus decreases the kernel time needed to complete the command

NFS v4

• 
  • Tested kernels use about the same amount of kernel time to complete the command.
• 
  • 2.6.36 kernels use less kernel time than 2.6.38 kernels.

RPC ops

NFS v3

• 
  • The tested kernels use about the same number of RPC operations.
• 
  • Using readdir plus results in fewer RPC operations to remove the directory

NFS v4

• 
  • All tested kernels issue the same number of RPC operations to remove directories
• 
  • All tested kernels issue almost the same number of RPC operations to remove directories