ab(8)

NAME
ab - Apache HTTP server benchmarking tool

SYNOPSIS
ab [ -k ] [ -e ] [ -q ] [ -S ] [ -i ] [ -s ] [ -n requests ] [ -t timelimit ] [ -c concurrency ] [ -p POST file ] [ -A Authenticate username:password ] [ -X proxy [ :port ] ] [ -P Proxy Authenticate username:password ] [ -H Custom header ] [ -C Cookie name=value ] [ -T content-type ] [ -v verbosity ] [ -w output HTML ] [ -g output GNUPLOT ] [ -e output CSV ] [ -x <table> attributes ] [ -y <tr> attributes ] [ -z <td> attributes ] [http[s]://]hostname[:port]/path ab [ -V ] [ -h ]

DESCRIPTION
ab is a tool for benchmarking the performance of your Apache HyperText Transfer Protocol (HTTP) server. It does this by giving you an indication of how many requests per second your Apache installation can serve.

OPTIONS

-k  Enable the HTTP KeepAlive feature; that is, perform multiple requests within one HTTP session. Default is no KeepAlive.

-d  Do not display the "percentage served within XX [ms] table". (legacy support).

-S  Do not display the median and standard deviation values, nor display the warning/error messages when the average and median are more than one or two times the standard deviation apart. And default to the min/avg/max values. (legacy support).

-s  When compiled in (ab -h will show you) use the SSL protected https rather than the http protocol. This feature is experimental and very rudimentary. You propably do not want to use it.

-k  Enable the HTTP KeepAlive feature; that is, perform multiple requests within one HTTP session. Default is no KeepAlive. -i Use an HTTP 'HEAD' instead of the GET method. Cannot be mixed with POST.

-n requests
    The number of requests to perform for the benchmarking session. The default is to perform just one single request, which will not give representative benchmarking results.

-t timelimit
    The number of seconds to spend benchmarking. Using this option automatically set the number of requests for the benchmarking session to 50000. Use this to benchmark the server for a fixed period of time. By default, there is no timelimit.

-c concurrency
    The number of simultaneous requests to perform. The default is to perform one HTTP request at at time, that is, no concurrency.

-p POST file
    A file containing data that the program will send to the Apache server in any HTTP POST requests.

-A Authorization username:password
    Supply Basic Authentication credentials to the server. The username and password are separated by a single ':', and sent as uuencoded data. The string is sent regardless of whether the server needs it; that is, has sent a 401 Authentication needed.

-X proxy[:port]
    Route all requests through the proxy (at optional port).

-P Proxy-Authorization username:password
    Supply Basic Authentication credentials to a proxy en-route. The username and password are separated by a single ':', and sent as uuencoded data. The string is sent regardless of whether the proxy needs it; that is, has sent a 407 Proxy authentication needed.

-C Cookie name=value
    Add a 'Cookie:' line to the request. The argument is typically a 'name=value' pair. This option may be repeated.

-p Header string
    Append extra headers to the request. The argument is typically in the form of a valid header line, usually a colon separated field value pair, for example, 'Accept-Encoding: zip/zop;8bit'.

-T content-type
    The content-type header to use for POST data.

-g gnuplot file
    Write all measured values out as a 'gnuplot' or TSV (Tab separate values) file. This file can easily be imported into packages like Gnuplot, IDL, Mathematica, Igor or even Excel. The labels are on the first line of the file.

-q  When processing more than 150 requsts; ab outputs a progress count on stderr every 10% or 100 requests or so. The -q flag qill suppress these messages.

-e CSV file
    Write a Comma separated value (CSV) file which contains for each percentage (from 1% to 100%) the time (in milli seconds) it took to serve that percentage of the requests. This is usually more usefull than the 'gnuplot' file; as the results are already

-v  Sets the verbosity level. Level 4 and above prints information on headers, level 3 and above prints response codes (for example, 404, 200), and level 2 and above prints warnings and informational messages.

-w  Print out results in HTML tables. The default table is two columns wide, with a white background.

-x attributes
    The string to use as attributes for <table>. Attributes are inserted <table here >

-y attributes
    The string to use as attributes for <tr>.

-z attributes
    The string to use as attributes for <td>.

-V  Display the version number and exit.

-h  Display usage information.

BUGS
There are various statically declared buffers of fixed length. Combined with inefficient parsing of the command line arguments, the response headers from the server, and other external inputs, these buffers might overflow.

Ab does not implement HTTP/1.x fully; instead, it only accepts some 'expected' forms of responses.

The rather heavy use of strstr(3) by the program may skew performance results, since it uses significant CPU resources. Make sure that performance limits are not hit by ab before your server's limit is reached.

The HTML output is not as complete as the text output.

Up to version 1.3d ab has propably reported values way too low for most measurements; as a single timeout (which is usually in the order of seconds) will shift several thousands of millisecond responses by a considerable factor. This was further componded by a serious integer overrun which would for realistic run's (i.e. those longer than a few minutes) produce believable but totally bogus results. Thanks to Sander Temme for solving this riddle.

SEE ALSO
httpd(8)