[Title] Network performance tuning: rtl8139 => virtio

[Title]    Network performance tuning: rtl8139 => virtio
[Type]      Enhancement
[Module]    // Module Name - (Main / Sub)
[Priority]  // Importance : Critical / Major / Minor
[CQ#]       // CQ Issue Number
[Redmine#]  // Redmine Isuue Number
[Problem]   // Problem Description
[Cause]     // Cause Description
[Solution]  // Solution Description
[TestCase]  // Executed the test-target (How to)