How to test speed of an s3 bucket mounted via s3fs-fuse?

I have an s3 share that's mounted via s3fs-fuse and would like to run some speed tests to compare throughput on DreamHost's DreamObjects vs Amazon S3. Everything is mounted and working just fine (s3fs testbucket ~/mnt/test -o passwd_file=/path/to/passwd-s3fs -o url=http://objects-us-west-1.dream.io), but traditional tests like dd and hdparm just don't work out. Any recommendations on running a successful speed test on a block storage device in such a scenario?