Virtual accelerators in a virtualized computing system

1. A method of virtualizing a hardware accelerator in a host cluster of a virtualized computing system, comprising:

commanding, at an initiator host in the host cluster, a programmable expansion bus device to reconfigure as a virtual accelerator based on specifications of a hardware accelerator in a target host of the host cluster;

executing, in the programmable expansion bus device, software to emulate the virtual accelerator as connected to an expansion bus of the initiator host;

receiving, at the programmable expansion bus device, compute tasks from an application executing in the initiator host; and

sending, to the target host, the compute tasks for processing by the hardware accelerator.

2. The method of claim 1 , wherein the programmable expansion bus device comprises a network interface card (NIC) having processing hardware and software executing on the processing hardware.

3. The method of claim 1 , wherein the compute tasks comprise binary code in a first format, and wherein the programmable expansion bus device is configured to translate the binary code from the first format into a second format before sending the compute tasks to the target host.

4. The method of claim 3 , wherein the programmable expansion bus device is configured to cache translations of the compute tasks.

5. The method of claim 1 , wherein the compute tasks comprise binary code in a first format, and wherein the target host is configured to translate the binary code from the first format to a second format.

6. The method of claim 1 , further comprising:

receiving, at the programmable expansion bus device, results from the target host generated by the hardware accelerator in response to performing the compute tasks; and

returning the results to the application.

7. The method of claim 6 , wherein the programmable expansion bus device is configured to cache the results in association with a signature of the compute tasks.

8. A non-transitory computer readable medium comprising instructions to be executed in a computing device to cause the computing device to carry out a method of virtualizing a hardware accelerator in a host cluster of a virtualized computing system, comprising:

commanding, at an initiator host in the host cluster, a programmable expansion bus device to reconfigure as a virtual accelerator based on specifications of a hardware accelerator in a target host of the host cluster;

executing, in the programmable expansion bus device, software to emulate the virtual accelerator as connected to an expansion bus of the initiator host;

receiving, at the programmable expansion bus device, compute tasks from an application executing in the initiator host; and

sending, to the target host, the compute tasks for processing by the hardware accelerator.

9. The non-transitory computer readable medium of claim 8 , wherein the programmable expansion bus device comprises a network interface card (NIC) having processing hardware and software executing on the processing hardware.

10. The non-transitory computer readable medium of claim 8 , wherein the compute tasks comprise binary code in a first format, and wherein the programmable expansion bus device is configured to translate the binary code from the first format into a second format before sending the compute tasks to the target host.

11. The non-transitory computer readable medium of claim 10 , wherein the programmable expansion bus device is configured to cache translations of the compute tasks.

12. The non-transitory computer readable medium of claim 8 , wherein the compute tasks comprise binary code in a first format, and wherein the target host is configured to translate the binary code from the first format to a second format.

13. The non-transitory computer readable medium of claim 8 , further comprising:

receiving, at the programmable expansion bus device, results from the target host generated by the hardware accelerator in response to performing the compute tasks; and

returning the results to the application.

14. The non-transitory computer readable medium of claim 13 , wherein the programmable expansion bus device is configured to cache the results in association with a signature of the compute tasks.

15. A host computer, comprising:

a hardware platform configured to execute an application having compute tasks;

a programmable expansion bus device in the hardware platform, the programmable expansion bus device configured to:

reconfigure as a virtual accelerator based on specifications of a hardware accelerator in a target host in network communication with the host computer;

execute software to emulate the virtual accelerator as connected to an expansion bus of the hardware platform;

receive the compute tasks from the application; and

send, to the target host, the compute tasks for processing by the hardware accelerator.

16. The host computer of claim 15 , wherein the programmable expansion bus device comprises a network interface card (NIC) having processing hardware and software executing on the processing hardware.

17. The host computer of claim 15 , wherein the compute tasks comprise binary code in a first format, and wherein the programmable expansion bus device is configured to translate the binary code from the first format into a second format before sending the compute tasks to the target host.

18. The host computer of claim 17 , wherein the programmable expansion bus device is configured to cache translations of the compute tasks.

19. The host computer of claim 15 , wherein the compute tasks comprise binary code in a first format, and wherein the target host is configured to translate the binary code from the first format to a second format.

20. The host computer of claim 15 , wherein the programmable expansion bus device is configured to:

receive results from the target host generated by the hardware accelerator in response to performing the compute tasks; and

return the results to the application.