HappinessNow
September 24th, 2009, 08:42 AM
Tornado (http://www.tornadoweb.org/) is an open source version of the scalable, non-blocking web server and tools that power FriendFeed (http://friendfeed.com/). The FriendFeed application is written using a web framework that looks a bit like web.py (http://webpy.org/) or Google's webapp (http://code.google.com/appengine/docs/python/tools/webapp/), but with additional tools and optimizations to take advantage of the underlying non-blocking infrastructure.
The framework is distinct from most mainstream web server frameworks (and certainly most Python frameworks) because it is non-blocking and reasonably fast. Because it is non-blocking and uses epoll (http://www.kernel.org/doc/man-pages/online/pages/man4/epoll.4.html), it can handle thousands of simultaneous standing connections, which means it is ideal for real-time web services. We built the web server specifically to handle FriendFeed's real-time features — every active user of FriendFeed maintains an open connection to the FriendFeed servers. (For more information on scaling servers to support thousands of clients, see The C10K problem (http://www.kegel.com/c10k.html).)
See the Tornado documentation (http://www.tornadoweb.org/documentation) for a detailed walkthrough of the framework.
Download and install
Download: tornado-0.2.tar.gz (http://www.tornadoweb.org/static/tornado-0.2.tar.gz)
tar xvzf tornado-0.2.tar.gz
cd tornado-0.2
python setup.py build
sudo python setup.py install The Tornado source code is hosted on GitHub (http://github.com/facebook/tornado).
Prerequisites
Tornado has been tested on Python 2.5 and 2.6. To use all of the features of Tornado, you need to have PycURL (http://pycurl.sourceforge.net/) and a JSON library like simplejson (http://pypi.python.org/pypi/simplejson/) installed. Complete installation instructions for...Ubuntu are included below for convenience.
Ubuntu Linux
sudo apt-get install python-dev python-pycurl python-simplejsonhttp://www.tornadoweb.org/
Performance
Web application performance is generally bound by architecture, not frontend performance. That said, Tornado is pretty fast relative to most popular Python web frameworks.
We ran a few remedial load tests on a simple "Hello, world" application in each of the most popular Python web frameworks (Django (http://www.djangoproject.com/), web.py (http://webpy.org/), and CherryPy (http://www.cherrypy.org/)) to get the baseline performance of each relative to Tornado. We used Apache/mod_wsgi for Django and web.py and ran CherryPy as a standalone server, which was our impression of how each framework is typically run in production environments. We ran 4 single-threaded Tornado frontends behind an nginx (http://nginx.net/) reverse proxy, which is how we recommend running Tornado in production (our load test machine had four cores, and we recommend 1 frontend per core).
We load tested each with Apache Benchmark (ab) on the a separate machine with the command
ab -n 100000 -c 25 http://10.0.1.x/The results (requests per second) on a 2.4GHz AMD Opteron processor with 4 cores:
http://ubuntuforums.org/attachment.php?attachmentid=129580&d=1253778621
In our tests, Tornado consistently had 4X the throughput of the next fastest framework, and even a single standalone Tornado frontend got 33% more throughput even though it only used one of the four cores.
Not very scientific, but at a high level, it should give you a sense that we have cared about performance as we built Tornado, and it shouldn't add too much latency to your apps relative to most Python web development frameworks.http://www.tornadoweb.org/documentation
The framework is distinct from most mainstream web server frameworks (and certainly most Python frameworks) because it is non-blocking and reasonably fast. Because it is non-blocking and uses epoll (http://www.kernel.org/doc/man-pages/online/pages/man4/epoll.4.html), it can handle thousands of simultaneous standing connections, which means it is ideal for real-time web services. We built the web server specifically to handle FriendFeed's real-time features — every active user of FriendFeed maintains an open connection to the FriendFeed servers. (For more information on scaling servers to support thousands of clients, see The C10K problem (http://www.kegel.com/c10k.html).)
See the Tornado documentation (http://www.tornadoweb.org/documentation) for a detailed walkthrough of the framework.
Download and install
Download: tornado-0.2.tar.gz (http://www.tornadoweb.org/static/tornado-0.2.tar.gz)
tar xvzf tornado-0.2.tar.gz
cd tornado-0.2
python setup.py build
sudo python setup.py install The Tornado source code is hosted on GitHub (http://github.com/facebook/tornado).
Prerequisites
Tornado has been tested on Python 2.5 and 2.6. To use all of the features of Tornado, you need to have PycURL (http://pycurl.sourceforge.net/) and a JSON library like simplejson (http://pypi.python.org/pypi/simplejson/) installed. Complete installation instructions for...Ubuntu are included below for convenience.
Ubuntu Linux
sudo apt-get install python-dev python-pycurl python-simplejsonhttp://www.tornadoweb.org/
Performance
Web application performance is generally bound by architecture, not frontend performance. That said, Tornado is pretty fast relative to most popular Python web frameworks.
We ran a few remedial load tests on a simple "Hello, world" application in each of the most popular Python web frameworks (Django (http://www.djangoproject.com/), web.py (http://webpy.org/), and CherryPy (http://www.cherrypy.org/)) to get the baseline performance of each relative to Tornado. We used Apache/mod_wsgi for Django and web.py and ran CherryPy as a standalone server, which was our impression of how each framework is typically run in production environments. We ran 4 single-threaded Tornado frontends behind an nginx (http://nginx.net/) reverse proxy, which is how we recommend running Tornado in production (our load test machine had four cores, and we recommend 1 frontend per core).
We load tested each with Apache Benchmark (ab) on the a separate machine with the command
ab -n 100000 -c 25 http://10.0.1.x/The results (requests per second) on a 2.4GHz AMD Opteron processor with 4 cores:
http://ubuntuforums.org/attachment.php?attachmentid=129580&d=1253778621
In our tests, Tornado consistently had 4X the throughput of the next fastest framework, and even a single standalone Tornado frontend got 33% more throughput even though it only used one of the four cores.
Not very scientific, but at a high level, it should give you a sense that we have cared about performance as we built Tornado, and it shouldn't add too much latency to your apps relative to most Python web development frameworks.http://www.tornadoweb.org/documentation