It can be tricky to troubleshoot qos-test when a test won't execute. Add
an explanation of how to trace qgraph node connectivity and find which
node has the problem.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210412143437.727560-3-stefanha@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>