我在使用计算能力为2.0的GTX 480运行代码时遇到了一些问题。
如果我使用每个块1024个线程启动内核,就会出现以下错误:
========= CUDA-MEMCHECK
========= Program hit cudaErrorLaunchOutOfResources (error 7) due to "too many resources requested for launch" on CUDA API call to cudaLaunch.
========= Saved host backtrace up to driver entry point at error
========= Host Frame:/usr/lib/x86_64-linux-gnu/libcuda.so.1 [0x2ef613]
========= Host Frame:/usr/local/cuda-6.5/lib64/libcudart.so.6.5 (cudaLaunch + 0x17e) [0x3686e]
========= Host Frame:./bin/myProgram [0x3a50]
========= Host Frame:./bin/myProgram [0x388a]
========= Host Frame:./bin/myProgram [0x38e3]
========= Host Frame:./bin/myProgram [0x2a99]
========= Host Frame:./bin/myProgram [0x1410]
========= Host Frame:./bin/myProgram [0x1da0]
========= Host Frame:/lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main + 0xed) [0x2176d]
========= Host Frame:./bin/myProgram [0x1139]
=========
我运行了该程序多次,使用不同的块和线程数:
5 Blocks, 512 Threads per Block => Works
5 Blocks, 1024 Threads per Block => Error
10 Blocks, 512 Threads per Block => Works
10 Blocks, 1024 Threads per Block => Error
15 Blocks, 512 Threads per Block => Works
15 Blocks, 1024 Threads per Block => Error
我检查了使用的寄存器,看起来没问题。使用了这么多线程的内核是具有28个寄存器的“Function4”。所有其他内核每次调用只使用<<<1, 32>>>。
ptxas info : 0 bytes gmem
ptxas info : Function properties for _Z7function1Py
0 bytes stack frame, 0 bytes spill stores, 0 bytes spill loads
ptxas info : Compiling entry function '_Z13function2PyS_i' for 'sm_20'
ptxas info : Function properties for _Z13function2PyS_i
0 bytes stack frame, 0 bytes spill stores, 0 bytes spill loads
ptxas info : Used 22 registers, 52 bytes cmem[0]
ptxas info : Compiling entry function '_Z6function3PyiS_' for 'sm_20'
ptxas info : Function properties for _Z6function3PyiS_
0 bytes stack frame, 0 bytes spill stores, 0 bytes spill loads
ptxas info : Used 22 registers, 56 bytes cmem[0]
ptxas info : Compiling entry function '_Z17function4PyiiS_Phji' for 'sm_20'
ptxas info : Function properties for _Z17function4PyiiS_Phji
0 bytes stack frame, 0 bytes spill stores, 0 bytes spill loads
ptxas info : Used 28 registers, 72 bytes cmem[0]
我也在我的GTX 660上使用CC 3.0运行了这个程序,每个块1024个线程,没有遇到任何问题。不知道问题出在哪里,有人有什么想法吗?
-maxrregcount 28
(或24
)编译代码,看看是否影响了失败的情况。 - Robert Crovella