ab - Apache HTTP server benchmarking tool
ab [ -k ] [ -e ] [ -q ] [ -S ] [ -i ] [ + .B -s ] [ -n requests ] [ -t timelimit ] [ -c
concurrency ] [ -p POST file ] [ -A Authentication username:password ] [ -P Proxy Authen-
tication 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 ]
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
-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 bench-
Maximum number of seconds to spend for benchmarking. This implies -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 warn-
ing/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
-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.
Number of multiple requests to perform at a time. Default is one request at a
-p POST file
File containing data to POST.
-A Authentication username:password
Supply BASIC Authentication credentials to the server. The username and pass-
word 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
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 authentication 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.,
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, Mathe-
matica, 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
String to use as attributes for <table>. Attributes are inserted <table here
String to use as attributes for <tr>.
String to use as attributes for <td>.
-V Display version number and exit.
-h Display usage information.
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.
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 <firstname.lastname@example.org>
for solving this riddle.
March 2000 ab(1)