On Tue, Jan 14, 2020 at 9:28 AM Lewis Tian <[email protected]> wrote:
> When I run pagerank on Ubuntu, the code works fine. (the graph data is
> stored in web-NotreDame.txt, 21M)
>
21M isn't very large, it shouldn't present any special problems. We
probably have a bug that isn't just about file size:
> taseikyo@ubuntu:~/Desktop/osv/apps/my-pagerank-test$ ls
> Makefile module.py pagerank.c usr.manifest web-NotreDame.txt
>
> taseikyo@ubuntu:~/Desktop/osv/apps/my-pagerank-test$ make
> cc -pie -o pagerank pagerank.c
>
> taseikyo@ubuntu:~/Desktop/osv/apps/my-pagerank-test$ ll -h
> total 21M
> drwxrwxr-x 2 taseikyo taseikyo 4.0K Jan 14 11:59 ./
> drwxrwxr-x 128 taseikyo taseikyo 4.0K Jan 14 11:51 ../
> -rw-rw-r-- 1 taseikyo taseikyo 110 Jan 14 11:51 Makefile
> -rw-rw-r-- 1 taseikyo taseikyo 60 Jan 13 11:26 module.py
> -rwxrwxr-x 1 taseikyo taseikyo 17K Jan 14 11:59 pagerank*
> -rw-rw-r-- 1 taseikyo taseikyo 5.6K Jan 14 11:51 pagerank.c
> -rw-rw-r-- 1 taseikyo taseikyo 85 Jan 14 11:53 usr.manifest
> -rw-rw-r-- 1 taseikyo taseikyo 21M Jan 14 11:54 web-NotreDame.txt
>
> taseikyo@ubuntu:~/Desktop/osv/apps/my-pagerank-test$ ./pagerank
> Graph data:
>
> Nodes: 325729, Edges: 1497134
>
>
> Number of iteration to converge: 52
>
> Final Pagerank values:
> [0.002066 , 0.000181 , ...]
>
> Time spent: 0.896491 seconds.
>
> But when I build and run pagerank on osv, it fails to read the graph data
> (only read part of the graph).
>
> taseikyo@ubuntu:~/Desktop/osv$ ./scripts/build image=my-pagerank-test
> taseikyo@ubuntu:~/Desktop/osv$ ./scripts/run.py
> OSv v0.54.0-71-g69a0ce39
> eth0: 192.168.122.15
> Booted up in 338.86 ms
> Cmdline: /pagerank
>
> Graph data:
>
> Nodes: 325729, Edges: 1497134
>
> Fail to read data...
>
> From: 6 To: 119
>
> Here is part of the code:
>
> while (!feof(fp)) {
> fret = fscanf(fp, "%d%d", &fromnode, &tonode);
> if (fret == 0) {
> printf("Fail to read data...\n");
> printf("\n From: %d To: %d\n",fromnode, tonode);
> return -1;
> }
> ...
> }
>
>
Maybe we have a bug in fscanf or in the stdio reading layer?
Things I'd like you to please check:
1. Print a failure already if fret < 2 - since 1 is also a failure.
2. On failure, please print ftell(fp) - our position in the file (is it the
end? something in the middle?). Please also do a fgets() or a short fgetc()
loop or fread() to read the next available bytes, to try to understand by
fscanf() failed. Is the reading from the file failing, or is the parsing
failing?
> When I use a small graph (4 nodes, 7 edges), it runs normally.
>
> taseikyo@ubuntu:~/Desktop/osv$ ./scripts/build image=my-pagerank-test
> taseikyo@ubuntu:~/Desktop/osv$ ./scripts/run.py
> OSv v0.54.0-71-g69a0ce39
> eth0: 192.168.122.15
> Booted up in 356.44 ms
> Cmdline: /pagerank
>
> Graph data:
>
> Nodes: 4, Edges: 7
>
>
> Number of iteration to converge: 41
>
> Final Pagerank values:
>
> [0.159913 , 0.144016 , 0.144016 , 0.082809 ]
>
> Time spent: 0.693802 seconds.
>
> Is osv unable to read large files (bug?) I'll appreciate your help very
> much! : )
>
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