Performance comparison amount different cache mode of KVM

Host hardware info:

CPU:

CPU(s): 32
On-line CPU(s) list: 0-31
Thread(s) per core: 2
Core(s) per socket: 8
Socket(s): 2
NUMA node(s): 2
Vendor ID: GenuineIntel
CPU family: 6
Model: 63
Model name: Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz

Memory:132G

Raid controller:  Logic / Symbios Logic MegaRAID SAS-3 3008 

Disk:400 GB 

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Guest hardware info:

4 vCpu

8G memory

2 disks