Measure and Benchmark Time for Ruby Methods - ruby-on-rails

Question

How can i measure the time taken by a method and the individual statements in that method in Ruby. If you see the below method i want to measure the total time taken by the method and the time taken for database access and redis access. I do not want to write Benchmark.measure before every statement. Does the ruby interpreter gives us any hooks for doing this ?
def foo
# code to access database
# code to access redis.
end

Answer 1

The simplest way:
require 'benchmark'
def foo
time = Benchmark.measure {
code to test
}
puts time.real #or save it to logs
end
Sample output:
2.2.3 :001 > foo
5.230000 0.020000 5.250000 ( 5.274806)
Values are: cpu time, system time, total and real elapsed time.
Source: ruby docs.

Answer 2

You could use the Time object. (Time Docs)
For example,
start = Time.now
# => 2022-02-07 13:55:06.82975 +0100
# code to time
finish = Time.now
# => 2022-02-07 13:55:09.163182 +0100
diff = finish - start
# => 2.333432
diff would be in seconds, as a floating point number.

Answer 3

Use Benchmark's Report
require 'benchmark' # Might be necessary.
def foo
Benchmark.bm( 20 ) do |bm| # The 20 is the width of the first column in the output.
bm.report( "Access Database:" ) do
# Code to access database.
end
bm.report( "Access Redis:" ) do
# Code to access redis.
end
end
end
This will output something like the following:
user system total real
Access Database: 0.020000 0.000000 0.020000 ( 0.475375)
Access Redis: 0.000000 0.000000 0.000000 ( 0.000037)
<------ 20 -------> # This is where the 20 comes in. NOTE: This is not shown in output.
More information can be found here.

Answer 4

Many of the answers suggest the use of Time.now. But it is worth being aware that Time.now can change. System clocks can drift and might get corrected by the system's administrator or via NTP. It is therefore possible for Time.now to jump forward or back and give your benchmarking inaccurate results.
A better solution is to use the operating system's monotonic clock, which is always moving forward. Ruby 2.1 and above give access to this via:
start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
# code to time
finish = Process.clock_gettime(Process::CLOCK_MONOTONIC)
diff = finish - start # gets time is seconds as a float
You can read more details here. Also you can see popular Ruby project, Sidekiq, made the switch to monotonic clock.

Answer 5

A second thought, define the measure() function with Ruby code block argument can help simplify the time measure code:
def measure(&block)
start = Time.now
block.call
Time.now - start
end
# t1 and t2 is the executing time for the code blocks.
t1 = measure { sleep(1) }
t2 = measure do
sleep(2)
end

Answer 6

In the spirit of wquist's answer, but a little simpler, you could also do it like below:
start = Time.now
# code to time
Time.now - start