enqueue API takes too much time

[Fan_Z_2]

I enqueued 5 kernels for an in-order execution in my application.Noticed an unusual behaviar after timing the program.One kernel's enqueue API cost a lot more time than the others, almost as much as the actual kernels running time.The enqueue API should be very efficient according to my experience , so what may cause this stalling?

[Robert_I_Intel]

HI Fan,

1. Please let us know what Processor, Operating System, Graphics Driver Version, and Tool Version you are using
2. Please state steps to reproduce the issue as precisely as you possibly could
3. If you are using command line tools, please provide the full command line
4. If code is involved, it is great to create a small "Reproducer" sample and attach it to the message in the form of a zip file
5. If you don't want your code to be seen by other forum users, please send me a private message

Thank you!