NSURLSession performance is very slow on watchOS

Originator:josh
Number:rdar://22827099 Date Originated:9/23/2015
Status:Open Resolved:
Product:watchOS Product Version:2.0
Classification: Reproducible:Always
 
Summary:
Requests made using NSURLSession when running on watchOS 2 are very slow. Loading the same content via NSData vs.  NSURLSession can often result in a difference of 5-10x in the load time. This is causing various issues throughout our app, as well as a very poor user experience, as the time to complete tasks can be 5-10x longer than the same app running on watchOS 1.

Results of running this test app can be found in the ReadMe.md file of the attached sample code.

Steps to Reproduce:
1. Open attached sample project "urlTest"
2. Build and run urlTest WatchKit App target
3. Press the button to run the test
4. Times to load the test URL are displayed on screen.

Expected Results:
Requests made using NSURLSession on watchOS 2 should be comparable to the performance on watchOS 1.

Actual Results:
Performance is very poor, leading to a poor user experience, depending on the amount of URL requests that need to be made by the app.

Version:
Apple Watch Simulator Version 2.0 (SimulatorApp-621 CoreSimulator-179)
Xcode Version 7.0 (7A220)

Sample code can also be found at: https://github.com/joshbuhler/urlTest

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