First of all thanks to NVIDIA for the creation of CUDA.
This may be a total newbie question but you will soon understand
my confusion about the issues re: memory and threading in CUDA.
Below is an insert from someone else with an identical adapter to the one I have.
Namely the ZOTAC GeForce GTX 570.
The issues I have are the following;
A) The terminology!
Some state you can use 4 SMs at a time. Others have said 5.
Given the max 1536 threads per SM it appears as if only 1.5 blocks
can be used at full threading concurrently whereas 1536 threads may be scheduled?
The card per specs below state one may issue 1024 threads to one block but only 1536 to any one SM.
The number of Warps per SM is 32. So is the number of cores/SM.
Is this equivalent and thus ambiguous statements/terms?
The specs further state; “Run time limit on kernels: Yes”.
This to me is like saying “Q: When will we arrive at point X? A: Yes!”
In short, what is the timeout factor in s, ms or us alt. clockticks?
B) The number of maximum concurrent threads?
Is this 32x1.5 by the thread limit above or is it much more and if so, how much?
C) Finally. The Unified Memory.
On the card specified below, is this Unified Memory Max = L2 Cache Size (655360 bytes)
or is it = Total amount of constant memory: 65536 bytes
or is it = Total amount of shared memory per block: 49152 bytes
Many questions and very confusing with the near constant deviation in terminology used in the manuals and discussions so I for one hope any helpful soul can shed some light on this.
/Thanks in advance!
—GTX 570 specs—
CUDA Device Query (Runtime API) version (CUDART static linking)
Detected 1 CUDA Capable device(s)
Device 0: “GeForce GTX 570”
CUDA Driver Version / Runtime Version 8.0 / 7.5
CUDA Capability Major/Minor version number: 2.0
Total amount of global memory: 1280 MBytes (1342177280 bytes)
(15) Multiprocessors, ( 32) CUDA Cores/MP: 480 CUDA Cores
GPU Max Clock rate: 1560 MHz (1.56 GHz)
Memory Clock rate: 1900 Mhz
Memory Bus Width: 320-bit
L2 Cache Size: 655360 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(65536), 2D=(65536, 65535), 3D=(2048, 2048, 2048)
Maximum Layered 1D Texture Size, (num) layers 1D=(16384), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(16384, 16384), 2048 layers
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
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (65535, 65535, 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
CUDA Device Driver Mode (TCC or WDDM): WDDM (Windows Display Driver Model)
Device supports Unified Addressing (UVA): Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 1 / 0
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >