diff options
author | Yorick Peterse <yorickpeterse@gmail.com> | 2016-06-24 14:44:50 +0300 |
---|---|---|
committer | Yorick Peterse <yorickpeterse@gmail.com> | 2016-06-28 18:51:25 +0300 |
commit | d7b4f36a3cc691ba5684c1bbc48cc22c59228ca8 (patch) | |
tree | acedc8752ec4c14ab2054fd410785bdd35f69088 /lib/gitlab/metrics/system.rb | |
parent | 7a94432e18f5210abda85721810ca2a4e573de5d (diff) |
Use clock_gettime for all performance timestamps
Process.clock_gettime allows getting the real time in nanoseconds as
well as allowing one to get a monotonic timestamp. This offers greater
accuracy without the overhead of having to allocate a Time instance. In
general using Time.now/Time.new is about 2x slower than using
Process.clock_gettime(). For example:
require 'benchmark/ips'
Benchmark.ips do |bench|
bench.report 'Time.now' do
Time.now.to_f
end
bench.report 'clock_gettime' do
Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
end
bench.compare!
end
Running this benchmark gives:
Calculating -------------------------------------
Time.now 108.052k i/100ms
clock_gettime 125.984k i/100ms
-------------------------------------------------
Time.now 2.343M (± 7.1%) i/s - 11.670M
clock_gettime 4.979M (± 0.8%) i/s - 24.945M
Comparison:
clock_gettime: 4979393.8 i/s
Time.now: 2342986.8 i/s - 2.13x slower
Another benefit of using Process.clock_gettime() is that we can simplify
the code a bit since it can give timestamps in nanoseconds out of the
box.
Diffstat (limited to 'lib/gitlab/metrics/system.rb')
-rw-r--r-- | lib/gitlab/metrics/system.rb | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/lib/gitlab/metrics/system.rb b/lib/gitlab/metrics/system.rb index a7d183b2f94..82c18bb108b 100644 --- a/lib/gitlab/metrics/system.rb +++ b/lib/gitlab/metrics/system.rb @@ -34,13 +34,29 @@ module Gitlab # THREAD_CPUTIME is not supported on OS X if Process.const_defined?(:CLOCK_THREAD_CPUTIME_ID) def self.cpu_time - Process.clock_gettime(Process::CLOCK_THREAD_CPUTIME_ID, :millisecond) + Process. + clock_gettime(Process::CLOCK_THREAD_CPUTIME_ID, :millisecond).to_f end else def self.cpu_time - Process.clock_gettime(Process::CLOCK_PROCESS_CPUTIME_ID, :millisecond) + Process. + clock_gettime(Process::CLOCK_PROCESS_CPUTIME_ID, :millisecond).to_f end end + + # Returns the current real time in a given precision. + # + # Returns the time as a Float. + def self.real_time(precision = :millisecond) + Process.clock_gettime(Process::CLOCK_REALTIME, precision).to_f + end + + # Returns the current monotonic clock time in a given precision. + # + # Returns the time as a Float. + def self.monotonic_time(precision = :millisecond) + Process.clock_gettime(Process::CLOCK_MONOTONIC, precision).to_f + end end end end |