While working on some Python scripts on Ubuntu running on a Parallels VM, I noticed that calls to the Twitter REST api were incredibly slow. I also saw the same problem when just using
curl instead of Python. Oddly, it didn’t occur if I just accessed the url from a browser (Chrome). Even more oddly, it only occurs when accessing the Twitter REST api, not arbitrary websites.
The issue can be avoided by switching the VM from Shared networking to Bridged networking. The problem and workaround is consistently reproducible for me.
- MacBook Pro
- Parallels Desktop 7.0
- Ubuntu 12.04
- Python 2.7.3
import httplib conn = httplib.HTTPConnection("api.twitter.com") conn.request("GET", "/1/friends/ids.json?screen_name=twitter") print("status: %d" % conn.getresponse().status)
Shared Networking in Parallels VM:
$ time python test_twitter_api.py status: 200 real 0m10.135s user 0m0.028s sys 0m0.004s
Bridged Networking in Parallels VM
$ time python test_twitter_api.py status: 200 real 0m0.167s user 0m0.028s sys 0m0.012s
The difference is dramatic – the call to
conn.request() drops from 10 seconds to a fraction of a second. The above results also hold when just using
curl to access the api:
curl --get 'http://api.twitter.com/1/friends/ids.json' \ --data 'cursor=-1&screen_name=twitter' --verbose
Strangely, the issue only occurs when accessing the Twitter REST api – it doesn’t occur if you’re fetching other urls, or if you access the Twitter REST url from a browser.
So if you’re doing software development on a Parallels VM, make sure to enable Bridged Networking! (Click on the little web icon in the bottom right of your VM window, or go to
Virtual Machine → Configure → Hardware → Network)