module Benchmark
Overview
The Benchmark module provides methods for benchmarking Crystal code, giving detailed reports on the time and memory taken for each task.
Measure the number of iterations per second of each task
require "benchmark"
Benchmark.ips do |x|
x.report("short sleep") { sleep 0.01 }
x.report("shorter sleep") { sleep 0.001 }
end
This generates the following output showing the mean iterations per second, the mean times per iteration, the standard deviation relative to the mean, and a comparison:
short sleep 88.7 ( 11.27ms) (± 3.33%) 8.90× slower
shorter sleep 789.7 ( 1.27ms) (± 3.02%) fastest
Benchmark::IPS
defaults to 2 seconds of warmup time and 5 seconds of
calculation time. This can be configured:
require "benchmark"
Benchmark.ips(warmup: 4, calculation: 10) do |x|
x.report("sleep") { sleep 0.01 }
end
Make sure to always benchmark code by compiling with the --release
flag.
Measure the time to construct the string given by the expression: "a"*1_000_000_000
require "benchmark"
puts Benchmark.measure { "a"*1_000_000_000 }
This generates the following output:
0.190000 0.220000 0.410000 ( 0.420185)
This report shows the user CPU time, system CPU time, the sum of the user and system CPU times, and the elapsed real time. The unit of time is seconds.
Do some experiments sequentially using the #bm
method:
require "benchmark"
n = 5000000
Benchmark.bm do |x|
x.report("times:") do
n.times do
a = "1"
end
end
x.report("upto:") do
1.upto(n) do
a = "1"
end
end
end
The result:
user system total real
times: 0.010000 0.000000 0.010000 ( 0.008976)
upto: 0.010000 0.000000 0.010000 ( 0.010466)
Make sure to always benchmark code by compiling with the --release
flag.
Extended Modules
Defined in:
benchmark/bm.crbenchmark/ips.cr
benchmark.cr
Instance Method Summary
-
#bm(&)
Main interface of the
Benchmark
module. -
#ips(calculation = 5, warmup = 2, interactive = STDOUT.tty?, &)
Instruction per second interface of the
Benchmark
module. -
#measure(label = "", &) : BM::Tms
Returns the time used to execute the given block.
-
#memory(&)
Returns the memory in bytes that the given block consumes.
-
#realtime(&) : Time::Span
Returns the elapsed real time used to execute the given block.
Instance Method Detail
Main interface of the Benchmark
module. Yields a Job
to which
one can report the benchmarks. See the module's description.
Instruction per second interface of the Benchmark
module. Yields a Job
to which one can report the benchmarks. See the module's description.
The optional parameters calculation and warmup set the duration of
those stages in seconds. For more detail on these stages see
Benchmark::IPS
. When the interactive parameter is true
, results are
displayed and updated as they are calculated, otherwise all at once.
Returns the time used to execute the given block.
Returns the memory in bytes that the given block consumes.
Benchmark.memory { Array(Int32).new } # => 32
Returns the elapsed real time used to execute the given block.
Benchmark.realtime { "a" * 100_000 } # => 00:00:00.0005840