Intel® FPGA SDK for OpenCL™ Pro Edition: Programming Guide

ID 683846
Date 9/26/2022

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8.8. Emulator Environment Variables

Several environment variables are available to modify the behavior of the emulator.


Controls the number of identical emulator devices provided by the emulator platform. If not set, a single emulator device is available. Therefore, set this variable only if you want to emulate multiple devices.


Indicates a maximum number of threads that can be used by the emulator. The default value is 32, and the maximum value is 255. Each thread can run a single kernel.

If the application requires several kernels to be executing simultaneously, the CL_CONFIG_CPU_TBB_NUM_WORKERS should be set appropriately (to the number of kernels used or a higher value).


Set the amount of available OpenCL local memory, with units, for example: 8MB, 256KB, or 1024B.


Set the amount of available OpenCL private memory, with units, for example: 8MB, 256KB, or 1024B.


When you compile your OpenCL kernel for emulation, the channel depth is different from the channel depth generated when your kernel is compiled for hardware. You can change this behavior with the CL_CONFIG_CHANNEL_DEPTH_EMULATION_MODE environment variable. For details, see Emulating Channel Depth.