ab(1)
ab(1) USER COMMANDS ab(1)
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, per-
form 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 sup-
port).
-s When compiled in (bb -h will show you) use the
SSL protected https rather than the http proto-
col. This feature is experimental and very rudi-
mentary. You propably do not want to use it.
-k Enable the HTTP KeepAlive feature; that is, per-
form 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 bench-
marking session. The default is to perform just
one single request, which will not give
representative benchmarking results.
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ab(1) USER COMMANDS ab(1)
-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 Authen-
tication 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 argu-
ment is typically a 'name=value' pair. This
option may be repeated.
-p Header string
Append extra headers to the request. The argu-
ment is typically in the form of a valid header
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ab(1) USER COMMANDS ab(1)
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 Excell. The
labels are on the first line of the file.
-q When processing more than 150 requsts; ab out-
puts 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 infor-
mational messages.
-w Print out results in HTML tables. The default
table is two columns wide, with a white back-
ground.
-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>.
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ab(1) USER COMMANDS ab(1)
-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 perfor-
mance 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 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 fac-
tor. This was further componded by a serious interger over-
run 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)
Last change: October 1999 4
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