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RedHat 9 (Linux i386) - man page for ab (redhat section 1)

ab(1)							      General Commands Manual							     ab(1)

NAME
ab - Apache HTTP server benchmarking tool
SYNOPSIS
ab [ -k ] [ -e ] [ -q ] [ -S ] [ -i ] [ + .B -s ] [ -n requests ] [ -t timelimit ] [ -c concurrency ] [ -p POST file ] [ -A Authentication username:password ] [ -P Proxy Authentication username:password ] [ -H Custom header ] [ -C Cookie name=value ] [ -T content-type ] [ -X proxy [ :port ] ] [ -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 your Apache HyperText Transfer Protocol (HTTP) server. It is designed to give you an impression of how your current Apache installation performs. This especially shows you how many requests per second your Apache installation is capable of serv- ing.
OPTIONS
-k Enable the HTTP KeepAlive feature, i.e., perform multiple requests within one HTTP session. Default is no KeepAlive. -n requests Number of requests to perform for the benchmarking session. The default is to just perform a single request which usually leads to non-representative benchmarking results. -t timelimit Maximum number of seconds to spend for benchmarking. This implies -d Do not display the "percentage served within XX [ms] ta- ble". (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 (bb -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. a -n 50000 internally. Use this to benchmark the server within a fixed total amount of time. Per default there is no timelimit. -c concurrency Number of multiple requests to perform at a time. Default is one request at a time. -p POST file File containing data to POST. -A Authentication username:password Supply BASIC Authentication credentials to the server. The username and password are separated by a single ':' and sent on the wire uuencoded. The string is sent regardless of whether the server needs it; (i.e., has sent an 401 authentication needed). -X proxy[:port] Route all requests through the proxy (at optional port). -P Proxy-Authentication username:password Supply BASIC Authentication credentials to a proxy en-route. The username and password are separated by a single ':' and sent on the wire uuencoded. The string is sent regardless of whether the proxy needs it; (i.e., has sent an 407 proxy authentica- tion needed). -C Cookie name=value Add a 'Cookie:' line to the request. The argument is typically in the form of a 'name=value' pair. This field is repeatable. -p Header string Append extra headers to the request. The argument is typically in the form of a valid header line, containing a colon-separated field-value pair. (i.e., 'Accept-Encoding: zip/zop;8bit'). -T content-type 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 Excell. 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 Set verbosity level - 4 and above prints information on headers, 3 and above prints response codes (404, 200, etc.), 2 and above prints warnings and info. -w Print out results in HTML tables. Default table is two columns wide, with a white background. -x attributes String to use as attributes for <table>. Attributes are inserted <table here > -y attributes String to use as attributes for <tr>. -z attributes String to use as attributes for <td>. -V Display version number and exit. -h Display usage information.
BUGS
There are various statically declared buffers of fixed length. Combined with the lazy parsing of the command line arguments, the response headers from the server and other external inputs, this might bite you. It does not implement HTTP/1.x fully; only accepts some 'expected' forms of responses. The rather heavy use of strstr(3) shows up top in profile, which might indicate a performance problem; i.e., you would measure the ab performance rather than the server's.
SEE ALSO
httpd(8) The HTML output is not as complete as the text output. Up to version 1.3d ab has propably reported values way to low for most measurements; as a single timeout (which is usually in the order of seconds) will shift several thousands of milli-second responses by a considerable factor. This was further componded by a serious interger 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 <sander@covalent.net> for solving this riddle. March 2000 ab(1)