Appium on Android emulator execution is slow when swiping

Hi, I am trying to run Appium on Android Emulators. However, the execution is extremely slow when performing swipe operation. It always takes about 20 ~ 30 seconds.
My running environment:

Appium 1.7.0,
node v8.6,
java-client 5.0.2.
OS: Ubuntu 16.0.4,
Emulator: Android SDK 22 x86
Any helps to reduce the running time? Thx in advance.