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guruvyasa
Journeyman III

does opencl give wrong info about the devices?

I ran the ranlux random number generator posted in amd forums..on the GPU the information it is giving is:

Num platforms:       1

Platform Vendor:     Advanced Micro Devices, Inc.

Platform profile:    FULL_PROFILE

Platform version:    OpenCL 1.1 ATI-Stream-v2.2 (302)

Platform name:       ATI Stream

Platform extensions: cl_khr_icd cl_amd_event_callback

Device name:         Cedar

Device type:         GPU 

Device vendor ID:    4098

Max compute units:   2

Max work item dim:   3

Max work group size: 128

Max mem alloc size:  128 MiB

Global memory size:  512 MiB

Global memory cache: None

Local memory type:   Dedicated

Prof Timer Res:      1 ns

OpenCL Driver ver:   CAL 1.4.838

Building OpenCL program: Done

the max compute units is only 2 and global memory is 512MB.. My GPU is Radeon HD 6370M with 1GB memory..so is this correct?
On the other hand for CPU execution the CPU details are:
Num platforms:       1
Platform Vendor:     Advanced Micro Devices, Inc.
Platform profile:    FULL_PROFILE
Platform version:    OpenCL 1.1 ATI-Stream-v2.2 (302)
Platform name:       ATI Stream
Platform extensions: cl_khr_icd cl_amd_event_callback
Device name:         Intel(R) Core(TM) i7 CPU       Q 740  @ 1.73GHz
Device type:         CPU 
Device vendor ID:    4098
Max compute units:   8
Max work item dim:   3
Max work group size: 1024
Max mem alloc size:  512 MiB
Global memory size:  1024 MiB
Global memory cache: Read/Write cache
Local memory type:   Global memory
Prof Timer Res:      1 ns
OpenCL Driver ver:   2.0
Building OpenCL program: Done
however the speed of number generation on CPU is:
Generation speed:        44.20 million numbers per second
and that on GPU is :
Generation speed:        138.19 million numbers per second
So what exactly is happening here? the device info shows that CPU has more number of cores and memory but results show that GPU is better..please help me..i did not find the specs for AMD HD 6370M on the net..


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himanshu_gautam
Grandmaster

Hi,

The parameters returned for you device appear to be correct. As far as cores are concerned CPU & GPU have different architecture and cores have different implications in each case.

Your core i7 should most probably be a 4 core system but shows 8 cores due to hyperthreading. 

In GPUs a compute unit consistes of many stream processing units. Generally a compute unit has 80 spus(differnrt for NI devices) but cedar has 40spus per compute unit.

 

http://www.amd.com/us/products/notebook/graphics/amd-radeon-6000m/amd-radeon-6300m/Pages/amd-radeon-6300m.aspx#2

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