Strange behaviour of `--view-sched-dags`

LLVM Project
1

Hi all,
This is my first post about LLVM (sorry for any naivety I might ask).

I am trying to understand scheduling (and register allocation) algorithms, and I tried to print the scheduling DAG with --view-sched-dags. While it produced somedot files in the tmp folder, when I try to do:

dot -Tpng /tmp/dag.dot > test.png

I receive a lot of errors from graphviz saying that the dot file is malformed (errors concerning especially the labels of the nodes).

Any idea of why this is happening?

Thanks,
Giuseppe

2

Faced the same problem. Fixed by ⚙ D115649 Revert unnecessary and incorrect change made to GraphWriter. Getting latest souce should fixed your issue.

3

Hi @Shivam,
Thanks for your help, it is now working fine. Since we are here, I was wondering if you could suggest a tool to analyze those graphs (in my case those graphs can contain > 1000 nodes and > 500 edges).

I tried the normal dot suite, but all the edges are very hard to identify. I had a look at some other tool (like gephi), but I was not super-happy either.

Thanks for any other suggestion,
Giuseppe

4

Sorry @giuseros, I am not aware of that tool. I will let others to make suggestion or I will suggest you to ask on dev mailing list.

Thanks,
Shivam