Benchmarking Date.today vs. Time.now

# NOTE: This is from an older version of Rails / Ruby. The code should still work, but you'll probably find that Date is much faster than Time now.

require 'benchmark'

def bmd
	Benchmark.ms { 1000.times { puts Date.today } }
end

def bmt
	Benchmark.ms { 1000.times { puts Time.now } }
end

# you'll see that running 'bmt' is much faster than 'bmd'
# so in your views, if you're looking to output some strftime or something similar, use Time.now instead of Date.time

102.461099624634
132.434129714966
104.948043823242
101.39799118042
101.342916488647
100.467920303345
94.0859317779541
116.589069366455
94.5439338684082
97.1629619598389
average: 104.543399810791


bmd:

323.458909988403
259.627103805542
344.912052154541
207.971096038818
193.113088607788
221.312999725342
250.807046890259
230.386018753052
252.316951751709
224.37310218811

average: 250.827836990356


def month_name_d(month = Date.today.month)
  Date::MONTHNAMES[month]
end

def month_name_t(month = Time.now.month)
  Date::MONTHNAMES[month]
end

ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_d } }
 => 79.9229145050049 
ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_d } }
 => 78.8428783416748 
ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_d } }
 => 82.1850299835205 

ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_t } }
 => 2.17700004577637 
ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_t } }
 => 1.98602676391602 
ruby-1.8.7-p174 > Benchmark.ms { 1000.times { month_name_t } }
 => 2.27212905883789

also, see http://codelikezell.com/benchmarking-ruby-time-and-date-instantiation/