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cl-fast-relaxed-math and profiling tools

Altera_Forum
Honored Contributor II
‎08-15-2015 06:25 AM
1,189 Views

Hi, 

There are two questions: 

First : 

In OpenCL standard it provides the cl-fast-relaxed-math to speed up and could lack of accuracy. 

I test the OpenCL code with this flag on INTEL,NIVIDA and AMD platforms. 

It could gain a speedup ~1x. 

But I use the AOCL compiler to add cl-fast-relaxed-math while compiling the OpenCL kernel Code. 

It seems that it could not gain any performance. Is the AOCL library doesn't support this flag now ? 

 

Second : 

 

I write a OpenCL program and the program might execute EnqueueNDRange API many time(use the for loop to enqueue repeatedly). The host only executes API and READ/WRITE buffer. Although from host executes EnqueueNDRange and READ/WRITE buffer to the FPGA receive the API signal to execute kernel code will waste 10~100ms overhead. Because there is no profiling tool to profile the detail situation. Therefore could any one help this problem ? 

 

SDK : 14.1 

platform : DE5  

 

Thanks
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