THe performance with GPU backend

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I run the libgrapelite on A100 with datasets graph500-26 using BFS, the results are as follow:
- load graph: 1080.76 sec

- load application: 0.341124 sec

- run algorithm: 0.23278 sec

- print output: 57.175 sec
It's not faster than on the CPU ，what's wrong with it ? Is it OK ? According to the graph500-benchmark list 'https://graph500.org/?page_id=12' , the GPU performance with BFS -graph500-26 can be as high as 319.061 GTEPS , while in libgrape-lite , this results can be computed as 2*26*16/0.23=4.66GTEPS, is it too small ?

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Reproduce the reported BFS run on an A100 with the graph500-26 dataset and compare the load, application, algorithm, and output timings recorded in the issue. Check whether libgrape-lite's 4.66 GTEPS calculation is valid against the linked Graph500 results, then document the confirmed bottleneck or explain why the comparison is not equivalent.

Written by the indexing model from the issue text.