During the development of a web application, it’s useful to know what kind of load it can hold. Today the application’s speed is one of the most important indicators and it is worth taking it seriously. A slow running application can push your users away.
To check how much your application is ready for production, you can use some utilities to test your server performance. Slow request processing speed can also help to identify incorrect server settings or scripts.
We'll cover 2 tools for understanding server-side performance: Apache Benchmark (ab) and Siege.
Apache Benchmark (ab) is a single-threaded command-line tool used to measure the performance of HTTP web servers. Originally developed for testing the Apache HTTP server, it is mainly suitable for testing any web server. For example, you can compare the performance of Apache and Nginx servers and decide which server is more productive in your case.
ApacheBench is preinstalled in many modern distributions. To check it just type in the console:
Otherwise install the apache2-utils package, which includes ab:
sudo apt-get install apache2-utils
The syntax of the command is:
ab [options] [http[s]://]hostname[:port]/path
Let's send 200 requests to example.com, where 20 of them will be sent at the same time:
ab -c 20 -n 200 https://example.com/
-c - number of concurrent requests
-n - number of request
After some time we'll get results:
Server Software: ECS Server Hostname: example.com Server Port: 443 SSL/TLS Protocol: TLSv1.2,ECDHE-RSA-AES128-GCM-SHA256,2048,128 TLS Server Name: example.com Document Path: / Document Length: 1270 bytes Concurrency Level: 20 Time taken for tests: 5.148 seconds Complete requests: 200 Failed requests: 0 Total transferred: 324345 bytes HTML transferred: 254000 bytes Requests per second: 38.85 [#/sec] (mean) Time per request: 514.812 [ms] (mean) Time per request: 25.741 [ms] (mean, across all concurrent requests) Transfer rate: 61.53 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 345 379 14.8 381 419 Processing: 112 125 4.7 125 137 Waiting: 112 125 4.7 125 137 Total: 460 504 19.0 508 552 Percentage of the requests served within a certain time (ms) 50% 508 66% 515 75% 517 80% 521 90% 526 95% 531 98% 537 99% 541 100% 552 (longest request)
Note that ab sends requests as fast as possible.
The main indicators of site performance can be considered Requests per second, Time per request, as well as the response speed of the fastest and slowest response. You should also remember about the geographic distance of the tested web server.
Apache Benchmark supports many options.
For example, you can send POST request with a specific file and headers:
ab -p file.json -T application/json -H 'Authorization: PASS' -c 20 -n 200 https://example.com/api/v1/
-p - specifies the file
-H - authorization headers
-T - content-type headers
-c - number of concurrent requests
-n - number of request
Or set multiple cookies:
ab -c 20 -n 200 -H "Cookie: one_cookie=cookie_value1; two_cookie=cookie_value2" http://example.com/
All available options you can see below:
Options are: -n requests Number of requests to perform -c concurrency Number of multiple requests to make at a time -t timelimit Seconds to max. to spend on benchmarking This implies -n 50000 -s timeout Seconds to max. wait for each response Default is 30 seconds -b windowsize Size of TCP send/receive buffer, in bytes -B address Address to bind to when making outgoing connections -p postfile File containing data to POST. Remember also to set -T -u putfile File containing data to PUT. Remember also to set -T -T content-type Content-type header to use for POST/PUT data, eg. 'application/x-www-form-urlencoded' Default is 'text/plain' -v verbosity How much troubleshooting info to print -w Print out results in HTML tables -i Use HEAD instead of GET -x attributes String to insert as table attributes -y attributes String to insert as tr attributes -z attributes String to insert as td or th attributes -C attribute Add cookie, eg. 'Apache=1234'. (repeatable) -H attribute Add Arbitrary header line, eg. 'Accept-Encoding: gzip' Inserted after all normal header lines. (repeatable) -A attribute Add Basic WWW Authentication, the attributes are a colon separated username and password. -P attribute Add Basic Proxy Authentication, the attributes are a colon separated username and password. -X proxy:port Proxyserver and port number to use -V Print version number and exit -k Use HTTP KeepAlive feature -d Do not show percentiles served table. -S Do not show confidence estimators and warnings. -q Do not show progress when doing more than 150 requests -l Accept variable document length (use this for dynamic pages) -g filename Output collected data to gnuplot format file. -e filename Output CSV file with percentages served -r Don't exit on socket receive errors. -m method Method name -h Display usage information (this message) -I Disable TLS Server Name Indication (SNI) extension -Z ciphersuite Specify SSL/TLS cipher suite (See openssl ciphers) -f protocol Specify SSL/TLS protocol (SSL2, TLS1, TLS1.1, TLS1.2 or ALL)
Siege is similar to ab in many ways, but also has a number of interesting features. We will look at 3 examples.
First, install the utility:
sudo apt-get install siege
A simple example:
siege -b -c 10 -r 20 https://example.com
-c - send 10 competitive requests
-r - number of repetitions of the test
-b - option allows to run a test without delay for throughput benchmarking
In other words, we make 20 times 10 competitive requests to the webserver without delay. Requests will go even if there are no responses from the server.
The results of the test:
** SIEGE 4.0.4 ** Preparing 10 concurrent users for battle. The server is now under siege... Transactions: 200 hits Availability: 100.00 % Elapsed time: 12.78 secs Data transferred: 0.12 MB Response time: 0.63 secs Transaction rate: 15.65 trans/sec Throughput: 0.01 MB/sec Concurrency: 9.92 Successful transactions: 200 Failed transactions: 0 Longest transaction: 0.68 Shortest transaction: 0.57
Transactions - number of requests from all users.
Elapsed time - total duration of testing.
Data transferred - total amount of data transmitted by all simulated users. It includes both request bodies and their headers.
Response time - average time for which the server managed to respond to the client.
Transaction rate - average number of requests that the server managed to process per second.
Throughput - average amount of data transferred every second from the server to users.
Concurrency - number of simultaneous connections at which the server responds without delay.
Successful transactions - the number of requests the server answered.
Let's look at another example:
siege -d 5 -c 10 -t 60s https://example.com
-d - delay in seconds between sending requests. By default, it's equal to 3 and means that requests will be sent at random intervals from 1 to 3 seconds. We set 5 seconds, i.e. requests will be sent at random intervals between 1 and 5 seconds.
-t - limits the time to run the test and has priority over the -r option. When specifying a value, you can use the suffixes 's', 'm' and 'h' to determine the time in seconds, minutes and hours.
And the last most interesting example, which in some way allows us to simulate the behavior of a real user by sending requests to different pages and making different intervals between requests:
siege -d 5 -c 10 -t 60s -i -f ~/urls.txt
-f - set the path to the text file with a list of URLs that must be visited during the testing process
-i - forces to take the URL from the file randomly
SIEGE 4.0.4 Usage: siege [options] siege [options] URL siege -g URL Options: -V, --version VERSION, prints the version number. -h, --help HELP, prints this section. -C, --config CONFIGURATION, show the current config. -v, --verbose VERBOSE, prints notification to screen. -q, --quiet QUIET turns verbose off and suppresses output. -g, --get GET, pull down HTTP headers and display the transaction. Great for application debugging. -p, --print PRINT, like GET only it prints the entire page. -c, --concurrent=NUM CONCURRENT users, default is 10 -r, --reps=NUM REPS, number of times to run the test. -t, --time=NUMm TIMED testing where "m" is modifier S, M, or H ex: --time=1H, one hour test. -d, --delay=NUM Time DELAY, random delay before each requst -b, --benchmark BENCHMARK: no delays between requests. -i, --internet INTERNET user simulation, hits URLs randomly. -f, --file=FILE FILE, select a specific URLS FILE. -R, --rc=FILE RC, specify an siegerc file -l, --log[=FILE] LOG to FILE. If FILE is not specified, the default is used: /var/log/siege.log -m, --mark="text" MARK, mark the log file with a string. between .001 and NUM. (NOT COUNTED IN STATS) -H, --header="text" Add a header to request (can be many) -A, --user-agent="text" Sets User-Agent in request -T, --content-type="text" Sets Content-Type in request --no-parser NO PARSER, turn off the HTML page parser --no-follow NO FOLLOW, do not follow HTTP redirects
Based on the test results, you can approximately evaluate the server performance. You need also remember that a lot depends on the type of pages we are checking, their content, the geographic distance of the tested web server and other factors.