Valgrind 和 CUDA:报告的泄漏是真实的吗? [英] Valgrind and CUDA: Are reported leaks real?
问题描述
我的应用程序中有一个非常简单的 CUDA 组件.Valgrind 报告了大量泄漏和仍然可访问的问题，所有这些都与 cudaMalloc 调用有关.
I have a very simple CUDA component in my application. Valgrind reports a lot of leaks and still-reachables, all related to the cudaMalloc calls.
这些泄漏是真的吗?我为每个 cudaMalloc 调用 cudaFree.这个 valgrind 无法解释 GPU 内存分配吗?如果这些泄漏不是真的，我可以抑制它们并让 valgrind 只分析应用程序的非 GPU 部分吗?
Are these leaks real? I call cudaFree for every cudaMalloc. Is this valgrind's inability to interpret GPU memory allocation? If these leaks are not real, can I suppress them and have valgrind only analyse the non-gpu part of the application?
extern "C"
unsigned int *gethash(int nodec, char *h_nodev, int len) {
unsigned int *h_out = (unsigned int *)malloc(sizeof(unsigned int) * nodec);
char *d_in;
unsigned int *d_out;
cudaMalloc((void**) &d_in, sizeof(char) * len * nodec);
cudaMalloc((void**) &d_out, sizeof(unsigned int) * nodec);
cudaMemcpy(d_in, h_nodev, sizeof(char) * len * nodec, cudaMemcpyHostToDevice);
int blocks = 1 + nodec / 512;
cube<<<blocks, 512>>>(d_out, d_in, nodec, len);
cudaMemcpy(h_out, d_out, sizeof(unsigned int) * nodec, cudaMemcpyDeviceToHost);
cudaFree(d_in);
cudaFree(d_out);
return h_out;
}
Valgrind 输出的最后一点:
Last bit of the Valgrind output:
...
==5727== 5,468 (5,020 direct, 448 indirect) bytes in 1 blocks are definitely lost in loss record 506 of 523
==5727== at 0x402B965: calloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==5727== by 0x4843910: ??? (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x48403E9: ??? (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x498B32D: ??? (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x494A6E4: ??? (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x4849534: ??? (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x48191DD: cuInit (in /usr/lib/nvidia-319-updates/libcuda.so.319.60)
==5727== by 0x406B4D6: ??? (in /usr/lib/i386-linux-gnu/libcudart.so.5.0.35)
==5727== by 0x406B61F: ??? (in /usr/lib/i386-linux-gnu/libcudart.so.5.0.35)
==5727== by 0x408695D: cudaMalloc (in /usr/lib/i386-linux-gnu/libcudart.so.5.0.35)
==5727== by 0x804A006: gethash (hashkernel.cu:36)
==5727== by 0x804905F: chkisomorphs (bdd.c:326)
==5727==
==5727== LEAK SUMMARY:
==5727== definitely lost: 10,240 bytes in 6 blocks
==5727== indirectly lost: 1,505 bytes in 54 blocks
==5727== possibly lost: 7,972 bytes in 104 blocks
==5727== still reachable: 626,997 bytes in 1,201 blocks
==5727== suppressed: 0 bytes in 0 blocks
推荐答案
valgrind 报告一堆 CUDA 内容的误报是一个已知问题.避免看到它的最佳方法是使用 valgrind 抑制，您可以在此处阅读所有相关信息:http://valgrind.org/docs/manual/manual-core.html#manual-核心.抑制
It's a known issue that valgrind reports false-positives for a bunch of CUDA stuff. The best way to avoid seeing it would be to use valgrind suppressions, which you can read all about here: http://valgrind.org/docs/manual/manual-core.html#manual-core.suppress
如果您想开始研究更接近您的具体问题的内容，可以在 Nvidia 开发论坛上发布一篇有趣的文章.它有一个指向示例抑制规则文件的链接.https://devtalk.nvidia.com/default/topic/404607/valgrind-3-4-suppressions-a-little-howto/
If you want to jumpstart into something a little closer to your specific issue, an interesting post is this one on the Nvidia dev forums. It has a link to a sample suppression rule file. https://devtalk.nvidia.com/default/topic/404607/valgrind-3-4-suppressions-a-little-howto/
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