Number of threads in GeForce GTX 560Ti

Question

I ran the deviceQuery and got the following result

./deviceQuery Starting... 

 CUDA Device Query (Runtime API) version (CUDART static linking)

 Detected 1 CUDA Capable device(s)
 Device 0: "GeForce GTX 560 Ti"
 CUDA Driver Version / Runtime Version          5.0 / 5.0
 CUDA Capability Major/Minor version number:    2.1
 Total amount of global memory:                 1024 MBytes (1073283072 bytes)
 (8) Multiprocessors x ( 48) CUDA Cores/MP:    384 CUDA Cores
 GPU Clock rate:                                1701 MHz (1.70 GHz)
 Memory Clock rate:                             2052 Mhz
 Memory Bus Width:                              256-bit
 L2 Cache Size:                                 524288 bytes
 Max Texture Dimension Size (x,y,z)             1D=(65536), 2D=(65536,65535), 3D= (2048,2048,2048)    
 Max Layered Texture Size (dim) x layers        1D=(16384) x 2048, 2D=(16384,16384) x 2048
 Total amount of constant memory:               65536 bytes
 Total amount of shared memory per block:       49152 bytes
 Total number of registers available per block: 32768
 Warp size:                                     32
 Maximum number of threads per multiprocessor:  1536
 Maximum number of threads per block:           1024
 Maximum sizes of each dimension of a block:    1024 x 1024 x 64
 Maximum sizes of each dimension of a grid:     65535 x 65535 x 65535
 Maximum memory pitch:                          2147483647 bytes
 Texture alignment:                             512 bytes
 Concurrent copy and kernel execution:          Yes with 1 copy engine(s)
 Run time limit on kernels:                     Yes
 Integrated GPU sharing Host Memory:            No
 Support host page-locked memory mapping:       Yes
 Alignment requirement for Surfaces:            Yes
 Device has ECC support:                        Disabled
 Device supports Unified Addressing (UVA):      Yes
 Device PCI Bus ID / PCI location ID:           1 / 0
 Compute Mode:
 < Default (multiple host threads can use ::cudaSetDevice() with device simultaneously)  >

deviceQuery, CUDA Driver = CUDART, CUDA Driver Version = 5.0, CUDA Runtime Version = 5.0, NumDevs = 1, Device0 = GeForce GTX 560 Ti

My understanding is that I can create maximum of 65535 x 65535 x 65535 blocks with 1024 threads per block. Does that I can have 65535 x 65535 x 65535 x 1024 threads of maximum ? If not what is the maximum number of threads I can have ?

Can anyone clarify this doubt ?

Sagar Masuti Sagar Masuti · Accepted Answer · 2013-09-17T08:31:04

Your understanding is correct. You can launch 65535 x 65535 x 65535 x 1024 threads theoretically but due to resource constraints you may be not able to hit the maximum.

Number of threads in GeForce GTX 560Ti

2 Answers