AB(8) ab AB(8)
ab - Apache HTTP server benchmarking tool
ab [ -A auth-username:password ] [ -b windowsize ] [ -c concurrency ] [ -C cookie-name=value ] [ -d ] [ -e csv-file ] [ -f protocol ] [ -g
gnuplot-file ] [ -h ] [ -H custom-header ] [ -i ] [ -k ] [ -n requests ] [ -p POST-file ] [ -P proxy-auth-username:password ] [ -q ] [ -r ]
[ -s ] [ -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 ciphersuite ] [http[s]://]hostname[:port]/path
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-
Supply BASIC Authentication credentials to the server. The username 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).
Size of TCP send/receive buffer, in bytes.
Number of multiple requests to perform at a time. Default is one request at a time.
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).
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'.
Specify SSL/TLS protocol (SSL2, SSL3, TLS1, or ALL).
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.
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 requests within one HTTP session. Default is no KeepAlive.
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.
File containing data to POST. Remember to also set -T.
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
-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 sup-
press these messages.
-r Don't exit on socket receive errors.
-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 probably do not want to use it.
-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).
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.
Content-type header to use for POST/PUT data, eg. application/x-www-form-urlencoded. Default: text/plain.
File containing data to PUT. Remember to also set -T.
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.
String to use as attributes for <table>. Attributes are inserted <table here >.
Use a proxy server for the requests.
String to use as attributes for <tr>.
String to use as attributes for <td>.
Specify SSL/TLS cipher suite (See openssl ciphers).
DESCRIPTION OF OUTPUT
The following list describes the values returned by ab:
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.
The DNS or IP address given on the command line
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.
The protocol parameters negotiated between the client and server. This will only be printed if SSL is used.
The request URI parsed from the command line string.
This is size in bytes of the first succesfully returning document. If the document length changes during testing, the response is
considered an error.
The number of concurrent clients used during the test
Time taken for tests
This is the time taken from the moment the first socket connection is created to the moment the last response is recieved
The number of successful responses recieved
The number of requests that were considered a failure. If the number is greater than zero, another line will be printed showing the
numer of requests that failed due to connecting, reading, incorrect content length, or exceptions.
The number of errors that failed during write (broken pipe).
The number of responses that were not in the 200 series of response codes. If all responses were 200, this field is not printed.
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.
The total number of bytes received from the server. This number is essentially the number of bytes sent over the wire.
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 result 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
The rate of transfer as calculated by the formula totalread / 1024 / timetaken
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.
Apache HTTP Server 2012-04-09 AB(8)