AB(1) ab AB(1)
NAME
ab - Apache HTTP server benchmarking tool
SYNOPSIS
ab [ -A auth-username:password ] [ -b windowsize ] [ -B local-address ]
[ -c concurrency ] [ -C cookie-name=value ] [ -d ] [ -e csv-file ] [ -E
client-certificate file ] [ -f protocol ] [ -g gnuplot-file ] [ -h ] [
-H custom-header ] [ -i ] [ -k ] [ -l ] [ -m HTTP-method ] [ -n requests
] [ -p POST-file ] [ -P proxy-auth-username:password ] [ -q ] [ -r ] [
-s timeout ] [ -S ] [ -t timelimit ] [ -T content-type ] [ -u PUT-file ]
[ -v verbosity] [ -V ] [ -w ] [ -x <table>-attributes ] [ -X
proxy[:port] ] [ -y <tr>-attributes ] [ -z <td>-attributes ] [ -Z ci-
phersuite ] [http[s]://]hostname[:port]/path
SUMMARY
ab is a tool for benchmarking your Apache Hypertext Transfer Protocol
(HTTP) server. It is designed to give you an impression of how your cur-
rent Apache installation performs. This especially shows you how many
requests per second your Apache installation is capable of serving.
OPTIONS
-A auth-username:password
Supply BASIC Authentication credentials to the server. The user-
name and password are separated by a single : and sent on the
wire base64 encoded. The string is sent regardless of whether the
server needs it (i.e., has sent an 401 authentication needed).
-b windowsize
Size of TCP send/receive buffer, in bytes.
-B local-address
Address to bind to when making outgoing connections.
-c concurrency
Number of multiple requests to perform at a time. Default is one
request at a time.
-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.
-d Do not display the "percentage served within XX [ms] table".
(legacy support).
-e csv-file
Write a Comma separated value (CSV) file which contains for each
percentage (from 1% to 100%) the time (in milliseconds) it took
to serve that percentage of the requests. This is usually more
useful than the 'gnuplot' file; as the results are already
'binned'.
-E client-certificate-file
When connecting to an SSL website, use the provided client cer-
tificate in PEM format to authenticate with the server. The file
is expected to contain the client certificate, followed by inter-
mediate certificates, followed by the private key. Available in
2.4.36 and later.
-f protocol
Specify SSL/TLS protocol (SSL2, SSL3, TLS1, TLS1.1, TLS1.2, or
ALL). TLS1.1 and TLS1.2 support available in 2.4.4 and later.
-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.
-h Display usage information.
-H custom-header
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").
-i Do HEAD requests instead of GET.
-k Enable the HTTP KeepAlive feature, i.e., perform multiple re-
quests within one HTTP session. Default is no KeepAlive.
-l Do not report errors if the length of the responses is not con-
stant. This can be useful for dynamic pages. Available in 2.4.7
and later.
-m HTTP-method
Custom HTTP method for the requests. Available in 2.4.10 and
later.
-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.
-p POST-file
File containing data to POST. Remember to also set -T.
-P proxy-auth-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 base64 encoded. The string is sent regardless of whether the
proxy needs it (i.e., has sent an 407 proxy authentication
needed).
-q When processing more than 150 requests, ab outputs a progress
count on stderr every 10% or 100 requests or so. The -q flag will
suppress these messages.
-r Don't exit on socket receive errors.
-s timeout
Maximum number of seconds to wait before the socket times out.
Default is 30 seconds. Available in 2.4.4 and later.
-S Do not display the median and standard deviation values, nor dis-
play the warning/error messages when the average and median are
more than one or two times the standard deviation apart. And de-
fault to the min/avg/max values. (legacy support).
-t timelimit
Maximum number of seconds to spend for benchmarking. This implies
a -n 50000 internally. Use this to benchmark the server within a
fixed total amount of time. Per default there is no timelimit.
-T content-type
Content-type header to use for POST/PUT data, eg. application/x-
www-form-urlencoded. Default is text/plain.
-u PUT-file
File containing data to PUT. Remember to also set -T.
-v verbosity
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.
-V Display version number and exit.
-w Print out results in HTML tables. Default table is two columns
wide, with a white background.
-x <table>-attributes
String to use as attributes for <table>. Attributes are inserted
<table here >.
-X proxy[:port]
Use a proxy server for the requests.
-y <tr>-attributes
String to use as attributes for <tr>.
-z <td>-attributes
String to use as attributes for <td>.
-Z ciphersuite
Specify SSL/TLS cipher suite (See openssl ciphers)
OUTPUT
The following list describes the values returned by ab:
Server Software
The value, if any, returned in the server HTTP header of the
first successful response. This includes all characters in the
header from beginning to the point a character with decimal value
of 32 (most notably: a space or CR/LF) is detected.
Server Hostname
The DNS or IP address given on the command line
Server Port
The port to which ab is connecting. If no port is given on the
command line, this will default to 80 for http and 443 for https.
SSL/TLS Protocol
The protocol parameters negotiated between the client and server.
This will only be printed if SSL is used.
Document Path
The request URI parsed from the command line string.
Document Length
This is the size in bytes of the first successfully returned doc-
ument. If the document length changes during testing, the re-
sponse is considered an error.
Concurrency Level
The number of concurrent clients used during the test
Time taken for tests
This is the time taken from the moment the first socket connec-
tion is created to the moment the last response is received
Complete requests
The number of successful responses received
Failed requests
The number of requests that were considered a failure. If the
number is greater than zero, another line will be printed showing
the number of requests that failed due to connecting, reading,
incorrect content length, or exceptions.
Write errors
The number of errors that failed during write (broken pipe).
Non-2xx responses
The number of responses that were not in the 200 series of re-
sponse codes. If all responses were 200, this field is not
printed.
Keep-Alive requests
The number of connections that resulted in Keep-Alive requests
Total body sent
If configured to send data as part of the test, this is the total
number of bytes sent during the tests. This field is omitted if
the test did not include a body to send.
Total transferred
The total number of bytes received from the server. This number
is essentially the number of bytes sent over the wire.
HTML transferred
The total number of document bytes received from the server. This
number excludes bytes received in HTTP headers
Requests per second
This is the number of requests per second. This value is the re-
sult of dividing the number of requests by the total time taken
Time per request
The average time spent per request. The first value is calculated
with the formula concurrency * timetaken * 1000 / done while the
second value is calculated with the formula timetaken * 1000 /
done
Transfer rate
The rate of transfer as calculated by the formula totalread /
1024 / timetaken
BUGS
There are various statically declared buffers of fixed length. Combined
with the lazy parsing of the command line arguments, the response head-
ers 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.
Apache HTTP Server 2018-10-10 AB(1)
Generated by dwww version 1.16 on Tue Dec 16 07:04:18 CET 2025.