User and Reference Guide for the Intel® C++ Compiler 14.0
This topic only applies to IA-32 architecture targeting Intel® Graphics Technology. Intel® Graphics Technology is a preview feature.
Scheduling many threads helps hide the latency of some operations. However, a large number of threads can increase the cost of offloading, or negatively affect performance. By default, the runtime attempts to schedule hundreds of threads, depending on the real trip counts of the parallelized loops, but for some tests the best results can be achieved with a much smaller thread count, such as 32 or 64 threads.
To override the default maximum value of threads, use the GFX_MAX_THREAD_COUNT environment variable. For example, to set the maximum value of threads to 32, enter:
set GFX_MAX_THREAD_COUNT=32
To monitor the real thread count, set the GFX_LOG_OFFLOAD environment variable to 2.
To monitor the real thread count and the distribution of the parallel loop nest's iteration space, set the GFX_LOG_OFFLOAD environment variable to 3.
|
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice. Notice revision #20110804 |