ruby - what is the advantage of EventMachine -

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this test case, found em not faster general tcp server

the em server:

    require 'rubygems'     require 'benchmark'     require 'eventmachine'     class handler  < eventmachine::connection       def receive_data(data)             operation = proc                 # simulate long running request                  = []                 n = 5000                 in 1..n                     << rand(n)                     a.sort!                 end             end          # callback block execute once request fulfilled         callback = proc |res|             send_data "send_response\n"         end              puts data             em.defer(operation, callback)       end     end      eventmachine::run {       eventmachine.epoll       eventmachine::start_server("0.0.0.0", 8080, handler)       puts "listening..."     }

and benchmark test:

require 'rubygems' require 'benchmark' require 'socket' benchmark.bm |x|     x.report("times:")         in 1..20             tcpsocket.open "127.0.0.1", 8080 |s|                     s.send "#{i}th sending\n", 0                     if line = s.gets                     puts line                 end                 puts "#{i}th sending"             end         end     end end

simplicity compared threads, not speed. here more insights: eventmachine: fast , scalable event-driven i/o framework

the citation applies question:

a lot has been written fact event-driven programs not theoretically faster threaded ones, , true. in practice, think event-driven model easier work with, if want extremely high scalability , performance while still ensuring maximum robustness. write programs have run months or years without crashing, leaking memory, or exhibiting kind of lumpy performance, in practice, event-driven programming works better. now, here's problem event-driven programming: have write "backwards." threaded model stores program state (inefficiently) in local variables on runtime stack. in em have yourself, unintuitive programmers used threads. why i'm interested in fibers, because opens possibility of writing looks programmer blocking i/o, still evented , uses no threads.


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