Is nppi synchronous or asynchronous

Accelerated Computing GPU-Accelerated Libraries
1

Is nppi synchronous or asynchronous?
i use nppiYUV420ToBGR_8u_P3C3R and pinned memory ? can i get real covert time like:
time1;
nppiYUV420ToBGR_8u_P3C3R
time2-time1;

2

you should assume that it may be asynchronous and put a cudaDeviceSynchronize() call in after the npp call