19.5. Testing HTTP Throughput and Latency with httping

Problem

As always, your users are complaining "the web site is too slow! We're dying here!" But it seems OK to you. Isn't there some way you can make some objective measurements without having to master some expensive, complicated analysis tool?

Solution

While sophisticated HTTP server analysis tools are nice, and there are dozens of them, sometimes you just want something quick and easy. httping is an excellent utility for measuring HTTP server throughput and latency, and because it's a tiny command-line tool, you can easily run it from multiple locations via SSH.

Its simplest invocation is to test latency:

	$ httping -c4 -g http://www.oreilly.com
	PING www.oreilly.com:80 (http://www.oreilly.com):
	connected to www.oreilly.com:80, seq=0 time=177.37 ms
	connected to www.oreilly.com:80, seq=1 time=170.28 ms
	connected to www.oreilly.com:80, seq=2 time=165.71 ms
	connected to www.oreilly.com:80, seq=3 time=179.51 ms
	--- http://www.oreilly.com ping statistics ---
	4 connects, 4 ok, 0.00% failed
	round-trip min/avg/max = 165.7/173.2/179.5 ms

That's not too bad. This doesn't tell you how long it takes pages to load, only how long it takes the server to respond to a HEAD request, which means fetching only the page headers without the content. So, let's do a GET (-G) request, which fetches the whole page:

	$ httping -c4 -Gg http://www.oreilly.com
	PING www.oreilly.com:80 (http://www.oreilly.com):
	connected to www.oreilly.com:80, seq=0 time=1553.78 ms
	connected to www.oreilly.com:80, seq=1 time=2790.99 ms
	connected to www.oreilly.com:80, seq=2 time=2067.32 ms
	connected to www.oreilly.com:80, seq=3 time=2033.02 ms
	--- http://www.oreilly.com ping statistics ---
	4 connects, 4 ok, 0.00% failed
	round-trip min/avg/max = 1553.8/2111.3/2791.0 ms

That slowed it down a bit!

The -r switch tells httping to resolve the hostname only once, to remove DNS latency from its measurements:

	$ httping -c4 -Grg http://www.oreilly.com

You can test SSL-enabled sites with the -l switch:

	$ httping -c4 -lGg https://www.fictionalsslsite.org

To specify an alternate port, append it to the URL:

	$ httping -c4 -Gg http://www.fictionalsslsite.org:8080

httping will report the roundtrip time with the -b switch in kilobytes per second (not kilobits):

	$ httping -c4 -Gbg http://www.fictionalsslsite.org
	PING www.fictionalsslsite.org:80 (http://www.fictionalsslsite.org):
	connected to www.fictionalsslsite.org:80, seq=0 time=2553.96 ms 43KB/s

Use the -s switch to display return codes. Put it all together, and this is what you get:

	$ httping -c4 -Gsbrg http://www.oreilly.com
	PING www.oreilly.com:80 (http://www.oreilly.com):
	 75KB/sed to www.oreilly.com:80, seq=0 time=1567.91 ms 200 OK
	 72KB/sed to www.oreilly.com:80, seq=1 time=1618.20 ms 200 OK
	 18KB/sed to www.oreilly.com:80, seq=2 time=5869.12 ms 200 OK
	 58KB/sed to www.oreilly.com:80, seq=3 time=1979.43 ms 200 OK
	--- http://www.oreilly.com ping statistics ---
	4 connects, 4 ok, 0.00% failed
	round-trip min/avg/max = 1567.9/2758.7/5869.1 ms
	Transfer speed: min/avg/max = 18/56/75 KB

You can test a local server by specifying the hostname and port instead of the URL:

	$ httping -c4 -h xena -p 80

Discussion

Ubuntu Feisty ships with a buggy version of httping, so you may need to build it from sources to get SSL support and a few other features that seem to have fallen out.

Building from sources is easy; you'll need the OpenSSL development libraries, which on Debian are libssl-devel, and on Fedora are openssl-devel. Unpack the tarball and run:

	# make all
	# make install

That's all there is to it.

httping is also designed to be a Nagios plug-in. The command definition looks like this:

	define command{
	   command_name check_httping
	   command_line /usr/bin/httping -N 2 -c 1 -h $HOSTADDRESS$
	}

See Also