ab(8) 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 instal-lation installation
lation 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 devia-tion deviation
tion 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. Can-not Cannot
not be mixed with POST.
-n requests The number of requests to perform for the benchmarking session. The default is to per-form perform
form 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 num-ber number
ber 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 sep-arated separated
arated 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 warn-ings warnings
ings 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 signifi-cant significant
cant 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)
February 2004 ab(8)
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