cross-post: http://perlmonks.org/?node_id=1191821
Consider app.psgi:
#!perl use 5.024; use strictures; use Time::HiRes qw(sleep); sub mock_connect { my $how_long_it_takes = 3 + rand; sleep $how_long_it_takes; return $how_long_it_takes; } sub main { state $db_handle = mock_connect($dsn); return sub { [200, [], ["connect took $db_handle seconds\n"]] }; } my $dsn = 'dbi:blahblah'; # from config file my $app = main($dsn); Measuring plackup (HTTP::Server::PSGI: Accepting connections at http://0:5000/):
› perl -MBenchmark=timeit,timestr,:hireswallclock -E"say timestr timeit 10, sub { system q(curl http://localhost:5000) }" connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds connect took 3.0299610154043 seconds 2.93921 wallclock secs ( 0.03 usr + 0.06 sys = 0.09 CPU) @ 107.53/s (n=10) Measuring thrall (Starting Thrall/0.0305 (MSWin32) http server listening at port 5000):
› perl -MBenchmark=timeit,timestr,:hireswallclock -E"say timestr timeit 10, sub { system q(curl http://localhost:5000) }" connect took 3.77111188120125 seconds connect took 3.15455510265111 seconds connect took 3.77111188120125 seconds connect took 3.15455510265111 seconds connect took 3.77111188120125 seconds connect took 3.64333342488772 seconds connect took 3.15455510265111 seconds connect took 3.77111188120125 seconds connect took 3.85268922343767 seconds connect took 3.64333342488772 seconds 17.4764 wallclock secs ( 0.02 usr + 0.09 sys = 0.11 CPU) @ 90.91/s (n=10) This performance is not acceptable because the initialisation happens several times, despite the state variable. How do you make it so it happens only once?
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