# Benchmarking

# Installation

Bootstrapper includes a standardized release to evaluate build performance across hosting providers.

curl https://raw.githubusercontent.com/apisnetworks/apnscp-bootstrapper/master/bootstrap.sh | env RELEASE=benchmark bash

Check back in ~2 hours once installation completes, then run the following command:

IFS=$'\n' ; DATES=($((tail -n 1 /root/apnscp-bootstrapper.log | grep failed=0 ; grep -m 1 -P '^\d{4}-.*[u|p]=root' /root/apnscp-bootstrapper.log ) | awk '{print $1, $2}')) ; [[ ${#DATES[@]} -eq 2 ]] && python -c 'from datetime import datetime; import sys; format="%Y-%m-%d %H:%M:%S,%f";print datetime.strptime(sys.argv[1], format)-datetime.strptime(sys.argv[2], format)' "${DATES[0]}" "${DATES[1]}" || (echo -e "\n>>> Unable to verify Bootstrapper completed - is Ansible still running or did it fail? Last 10 lines follow" && tail -n 10 /root/apnscp-bootstrapper.log)

A duration will appear or the last 10 lines of /root/apnscp-bootstrapper.log if it failed. This duration tests network/IO/CPU.

A second test of backend performance once apnscp is setup gives the baseline performance between frontend/backend communication to a single vCPU. This can be tested as follows.

First update the shell with helpers from .bashrc,

exec $SHELL -i
# Then run the cpcmd helper
cpcmd scope:set cp.debug true  ; sleep 5 ; cpcmd test_backend_performance ; cpcmd scope:set cp.debug false

Enabling debug mode opens up the test module for instrumentation utilities.

# Converting to production

A server provisioned using the benchmark branch can be converted to a normal build without resetting the server. Use cpcmd to set any apnscp-vars.yml value; use the Customization Utility on ApisCP as cross-reference.

# Launch new bash shell with apnscp helper functions
exec $SHELL -i
cd /usr/local/apnscp
# Save remote URL, should be gitlab.com/apisnetworks/apnscp.git
REMOTE="$(git config --get remote.origin.url)"
git remote remove origin
git remote add -f -t master origin "$REMOTE"
git reset --hard origin/master
cpcmd scope:set cp.bootstrapper populate_filesystem_template true
# Set any other Bootstrapper values from apnscp-vars.yml...
# cpcmd config_set apnscp.bootstrapper varname varval
upcp -sb
# After Bootstrapper completes - it will take 5-30 minutes to do so
cpcmd scope:set cp.bootstrapper populate_filesystem_template auto
cpcmd auth:change-password newadminpassword
cpcmd common:set-email your@email.address

populate_filesystem_template must be enabled to update any packages that have been added/removed in ApisCP. Once everything is done, access ApisCP's interface to get started.

Bootstrapper project on GitHub contains a reference for provider performance. Not all providers are created equal and often times a "CPU" on VPS is shared n-ways sometimes with very noisy neighbors.

# HTTP

Before evaluating HTTP performance, it is necessary to disable Evasive's HTTP request protection. Disabling HTTP/1.0 protection may also be necessary depending upon the benchmark utility, such as ab, which sends requests using HTTP/1.0.

By default, a 2 minute delay is imposed before applying configuration changes to the HTTP server. This may be changed by adjusting [httpd] => reload_delay (see Apache.md). For example, a value of "now" disables any reload delay, but may expose a server to unintended DoS attacks during bulk account edits.

cpcmd scope:set apache.evasive enabled false
cpcmd scope:set apache.block10 false
# Now benchmark a site
ab -n 1000 -c 1 http://mydomain.com/

# Fast WordPress benchmark

Creating a test account to benchmark WordPress is simple with a few CLI commands. Once your done benchmarking, run DeleteDomain benchmark.test to remove it (or keep it around for a rainy day).

AddDomain -c siteinfo,domain=benchmark.test -c crontab,enabled=1 -c crontab,permit=1 -c ssh,enabled=1 -c dns,provider=null -c mail,provider=null -c siteinfo,admin_user=benchmark-user
grep -Eq "benchmark.test\b" /etc/hosts || (echo "$(cpcmd -d benchmark.test site:ip-address) benchmark.test" >> /etc/hosts)
cpcmd -d benchmark.test wordpress:install benchmark.test
cpcmd scope:set apache.evasive enabled false
cpcmd scope:set apache.block10 false
sleep 120
ab -k -n 1000 -c 1 http://benchmark.test/
DETAILS

Run the following commands to create a new domain named "benchmark.test". DNS and email will be disabled for the domain. Install WordPress, disable Evasive and HTTP/1.0 protection on the account. Sleep for 2 minutes for [httpd] => reload_delay to expire (at -l shows pending jobs), then run 1000 requests in serial against the domain.

TIP

Overriding your hosts file would allow you to access the WordPress administrative portal as if it were a real, resolvable domain. Use the IP from cpcmd -d benchmark.test site:ip-address.

# Extending

Let's take this one step further, configuring a WP Redis object cache. Use redis:create to create a new Redis instance for the account, then wp-cli to install a Redis cache plugin.

# Create a new Redis instance for benchmark.test named "wp-test" listening on /tmp/redis.sock
cpcmd -d benchmark.test redis:create wp-test '[unixsocket:/tmp/redis.sock]'
# Switch to benchmark.test account to configure plugin
su benchmark.test
cd /var/www/html
# Install Redis object cache plugin
wp-cli plugin install --activate redis-cache
# Define Redis path
wp-cli config set WP_REDIS_PATH /tmp/redis.sock

Redis configuration

Activate Redis cache and you're set!

wp-cli redis enable
# Verify it is running
wp-cli redis status

Exit out of the subshell, run as an unrestricted user, then verify data is cached:

exit
ab -n 10 -c 1 http://benchmark.test/
echo "KEYS *" | redis-cli -s /home/virtual/benchmark.test/tmp/redis.sock

# Concurrency

Benchmarks are designed to model real-world scenarios with artificial, deterministic usage patterns. It's an oxymoron to believe any such correlation exists between benchmarks and typical usage scenarios, but what benchmarks provide is the theoretical peak throughput. It's all downhill from there!

When evaluating the peak throughput do not run more than NPROC+1 instances. Linux has an intelligent scheduling algorithm to interleave parcels of work (threads). If for example a site is handling 5 concurrent requests over 250 ms, the processing is rarely contiguous due to network latency/output buffering. Benchmarking locally removes this barrier.

Let's assume a WordPress site on a two-core machine. Following this logic, benchmark figures should begin to stabilize after 3 concurrent requests. All requests are generated using ab as outlined above. The PHP-FPM pool was reconfigured from ondemand to static and the total worker count (pm.max_children) changed from 3 to 20 to

Concurrency Throughput (req/sec) % Δ Time per req (ms) % Δ
1 83.18 12.022
2 163.01 95.97% 6.135 -48.97%
3 169.12 3.75% 5.913 -3.63%
4 174.86 3.39% 5.719 -3.28%
5 174.61 -0.14% 5.727 0.14%
6 175.53 0.53% 5.697 -0.52%
7 174.73 -0.46% 5.723 0.46%
8 176.24 0.86% 5.674 -0.86%
9 175.65 -0.33% 5.693 0.33%
10 177.18 0.87% 5.644 -0.86%
15 175.89 -0.73% 5.685 0.73%
20 177.87 1.23% 5.622 -1.11%

ApisCP uses NPROC + 2 workers per site. Typically this is sufficient for optimal throughput except in high latency environments. PHP requests operate synchronously, which means the workers is only freed to handle a new request at the conclusion of the previous request. Theoretically, in the above benchmark, PHP could serve ~170 concurrent users per second with 4 PHP-FPM workers assuming a uniform distribution or 14.6 million pageviews per day. Often these figures are much lower in real-world, hampered by network latency both on the request and response.