Ayende @ Rahienhttp://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660Daniel commented on Small optimizations? Did you check that idiot checkbox yet?If a delegate closes over local variables, a helper class gets created, so a lambda translates into 2 allocations: the helper class and the delegate. If a delegate closes only over 'this', it gets compiled into an instance method. These aren't cached, so the lambda causes 1 allocation: the delegate. If a delegate doesn't close over any variables, then it gets compiled into a static method, and the delegate gets cached using a static field. Once the cache is filled, the lambda doesn't cause any heap allocations. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment7http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment7Thu, 14 Oct 2010 14:36:22 GMTMatt Warren commented on Small optimizations? Did you check that idiot checkbox yet?@configurator I *think* that if it uses fields it gets converted into a instance method, but I'm not entirely sure. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment6http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment6Wed, 13 Oct 2010 23:53:27 GMTconfigurator commented on Small optimizations? Did you check that idiot checkbox yet?Tobi is right. Non-closing delegates are converted to static methods. I don't know what happens to ones that use fields, but I'm pretty sure they're cached as well. Only when closing over locals you're creating a mess. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment5http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment5Wed, 13 Oct 2010 17:41:13 GMTDennis commented on Small optimizations? Did you check that idiot checkbox yet?Even so, the speed at which this allocation happens makes it just an insane micro optimization... Unless you are doing it billions of times. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment4http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment4Wed, 13 Oct 2010 12:03:07 GMTtobi commented on Small optimizations? Did you check that idiot checkbox yet?No! I think the C# compiler caches delegates that do not close over variables. I have seen that in reflector a while ago. The delegate gets written to a static field. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment3http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment3Wed, 13 Oct 2010 10:27:12 GMTAyende Rahien commented on Small optimizations? Did you check that idiot checkbox yet?Well, that was fast. Yep, that is it. http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment2http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment2Wed, 13 Oct 2010 10:24:09 GMTTorkel commented on Small optimizations? Did you check that idiot checkbox yet?Instead of newing a List you new up a delegate each call to GetOrAdd ? http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment1http://ayende.com/4660/small-optimizations-did-you-check-that-idiot-checkbox-yet#comment1Wed, 13 Oct 2010 10:21:40 GMT