{"action":"opened","issue":{"url":"https://api.github.com/repos/dotnet/corefx/issues/3588","labels_url":"https://api.github.com/repos/dotnet/corefx/issues/3588/labels{/name}","comments_url":"https://api.github.com/repos/dotnet/corefx/issues/3588/comments","events_url":"https://api.github.com/repos/dotnet/corefx/issues/3588/events","html_url":"https://github.com/dotnet/corefx/issues/3588","id":109373531,"number":3588,"title":"Perf: System.Collections List, Dictionary default constructors 2x slower on Linux","user":{"login":"ianhays","id":2606879,"avatar_url":"https://avatars.githubusercontent.com/u/2606879?v=3","gravatar_id":"","url":"https://api.github.com/users/ianhays","html_url":"https://github.com/ianhays","followers_url":"https://api.github.com/users/ianhays/followers","following_url":"https://api.github.com/users/ianhays/following{/other_user}","gists_url":"https://api.github.com/users/ianhays/gists{/gist_id}","starred_url":"https://api.github.com/users/ianhays/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ianhays/subscriptions","organizations_url":"https://api.github.com/users/ianhays/orgs","repos_url":"https://api.github.com/users/ianhays/repos","events_url":"https://api.github.com/users/ianhays/events{/privacy}","received_events_url":"https://api.github.com/users/ianhays/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/dotnet/corefx/labels/performance","name":"performance","color":"fbca04"},{"url":"https://api.github.com/repos/dotnet/corefx/labels/System.Collections","name":"System.Collections","color":"d4c5f9"},{"url":"https://api.github.com/repos/dotnet/corefx/labels/X-Plat","name":"X-Plat","color":"fbca04"}],"state":"open","locked":false,"assignee":{"login":"ellismg","id":9602953,"avatar_url":"https://avatars.githubusercontent.com/u/9602953?v=3","gravatar_id":"","url":"https://api.github.com/users/ellismg","html_url":"https://github.com/ellismg","followers_url":"https://api.github.com/users/ellismg/followers","following_url":"https://api.github.com/users/ellismg/following{/other_user}","gists_url":"https://api.github.com/users/ellismg/gists{/gist_id}","starred_url":"https://api.github.com/users/ellismg/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ellismg/subscriptions","organizations_url":"https://api.github.com/users/ellismg/orgs","repos_url":"https://api.github.com/users/ellismg/repos","events_url":"https://api.github.com/users/ellismg/events{/privacy}","received_events_url":"https://api.github.com/users/ellismg/received_events","type":"User","site_admin":false},"milestone":{"url":"https://api.github.com/repos/dotnet/corefx/milestones/3","html_url":"https://github.com/dotnet/corefx/milestones/1.0.0-rc1","labels_url":"https://api.github.com/repos/dotnet/corefx/milestones/3/labels","id":1248712,"number":3,"title":"1.0.0-rc1","description":"Nov 2015 (https://github.com/aspnet/Home/wiki/Roadmap)\r\n","creator":{"login":"joshfree","id":1302850,"avatar_url":"https://avatars.githubusercontent.com/u/1302850?v=3","gravatar_id":"","url":"https://api.github.com/users/joshfree","html_url":"https://github.com/joshfree","followers_url":"https://api.github.com/users/joshfree/followers","following_url":"https://api.github.com/users/joshfree/following{/other_user}","gists_url":"https://api.github.com/users/joshfree/gists{/gist_id}","starred_url":"https://api.github.com/users/joshfree/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/joshfree/subscriptions","organizations_url":"https://api.github.com/users/joshfree/orgs","repos_url":"https://api.github.com/users/joshfree/repos","events_url":"https://api.github.com/users/joshfree/events{/privacy}","received_events_url":"https://api.github.com/users/joshfree/received_events","type":"User","site_admin":false},"open_issues":113,"closed_issues":9,"state":"open","created_at":"2015-08-10T18:00:33Z","updated_at":"2015-10-01T20:08:41Z","due_on":"2015-11-18T08:00:00Z","closed_at":null},"comments":0,"created_at":"2015-10-01T20:08:40Z","updated_at":"2015-10-01T20:08:40Z","closed_at":null,"body":"Perf Tests:\r\n```\r\n[Benchmark]\r\npublic void ctor()\r\n{\r\n    foreach (var iteration in Benchmark.Iterations)\r\n        using (iteration.StartMeasurement())\r\n            for (int i = 0; i <= 20000; i++)\r\n            {\r\n                new Dictionary<int, string>(); new Dictionary<int, string>(); new Dictionary<int, string>();\r\n                new Dictionary<int, string>(); new Dictionary<int, string>(); new Dictionary<int, string>();\r\n                new Dictionary<int, string>(); new Dictionary<int, string>(); new Dictionary<int, string>();\r\n            }\r\n}\r\n\r\n[Benchmark]\r\npublic void ctor()\r\n{\r\n    foreach (var iteration in Benchmark.Iterations)\r\n        using (iteration.StartMeasurement())\r\n        {\r\n            for (int i = 0; i < 20000; i++)\r\n            {\r\n                new List<object>(); new List<object>(); new List<object>(); new List<object>(); new List<object>();\r\n                new List<object>(); new List<object>(); new List<object>(); new List<object>(); new List<object>();\r\n                new List<object>(); new List<object>(); new List<object>(); new List<object>(); new List<object>();\r\n            }\r\n        }\r\n}\r\n```\r\n\r\nLinux perf results for Dictionary:\r\n```\r\n       <performance runid=\"System.Collections.Tests.Perf_Dictionary.ctor-Linux\" etl=\"/home/ianha/uptonogood/results/System.Collections.Tests.Perf_Dictionary.ctor-Linux.csv\">\r\n          <metrics>\r\n            <Duration displayName=\"Duration\" unit=\"msec\" />\r\n          </metrics>\r\n          <iterations>\r\n            <iteration index=\"0\" Duration=\"9.1712999939918518\" />\r\n            <iteration index=\"1\" Duration=\"8.2485000193119049\" />\r\n            <iteration index=\"2\" Duration=\"8.0482999980449677\" />\r\n            <iteration index=\"3\" Duration=\"7.8631999790668488\" />\r\n            <iteration index=\"4\" Duration=\"7.6421999931335449\" />\r\n            <iteration index=\"5\" Duration=\"9.9480000138282776\" />\r\n            <iteration index=\"6\" Duration=\"7.70890000462532\" />\r\n            <iteration index=\"7\" Duration=\"8.2391000092029572\" />\r\n            <iteration index=\"8\" Duration=\"7.3601000010967255\" />\r\n            <iteration index=\"9\" Duration=\"9.1152999997138977\" />\r\n            <iteration index=\"10\" Duration=\"7.5229999721050262\" />\r\n            <iteration index=\"11\" Duration=\"7.875\" />\r\n            <iteration index=\"12\" Duration=\"7.6078000068664551\" />\r\n            <iteration index=\"13\" Duration=\"7.8296999931335449\" />\r\n            <iteration index=\"14\" Duration=\"7.7754999995231628\" />\r\n            <iteration index=\"15\" Duration=\"8.093999981880188\" />\r\n            <iteration index=\"16\" Duration=\"7.9314000010490417\" />\r\n            <iteration index=\"17\" Duration=\"8.45320001244545\" />\r\n            <iteration index=\"18\" Duration=\"8.0026000142097473\" />\r\n            <iteration index=\"19\" Duration=\"8.63510000705719\" />\r\n            <iteration index=\"20\" Duration=\"8.0227000117301941\" />\r\n            <iteration index=\"21\" Duration=\"8.5139000117778778\" />\r\n            <iteration index=\"22\" Duration=\"8.3104000091552734\" />\r\n            <iteration index=\"23\" Duration=\"8.0196000039577484\" />\r\n            <iteration index=\"24\" Duration=\"7.5029999911785126\" />\r\n            <iteration index=\"25\" Duration=\"8.4054999947547913\" />\r\n            <iteration index=\"26\" Duration=\"7.8804999887943268\" />\r\n            <iteration index=\"27\" Duration=\"7.717600017786026\" />\r\n            <iteration index=\"28\" Duration=\"7.83830001950264\" />\r\n            <iteration index=\"29\" Duration=\"7.713699996471405\" />\r\n            <iteration index=\"30\" Duration=\"9.368800014257431\" />\r\n            <iteration index=\"31\" Duration=\"7.9806999862194061\" />\r\n            <iteration index=\"32\" Duration=\"7.48810002207756\" />\r\n            <iteration index=\"33\" Duration=\"7.3455000221729279\" />\r\n            <iteration index=\"34\" Duration=\"7.0755999982357025\" />\r\n            <iteration index=\"35\" Duration=\"7.1823999881744385\" />\r\n            <iteration index=\"36\" Duration=\"7.7901999950408936\" />\r\n            <iteration index=\"37\" Duration=\"7.545199990272522\" />\r\n            <iteration index=\"38\" Duration=\"7.5584000051021576\" />\r\n            <iteration index=\"39\" Duration=\"7.9182000160217285\" />\r\n            <iteration index=\"40\" Duration=\"7.9902999997138977\" />\r\n            <iteration index=\"41\" Duration=\"7.370199978351593\" />\r\n            <iteration index=\"42\" Duration=\"7.6527999937534332\" />\r\n            <iteration index=\"43\" Duration=\"7.347599983215332\" />\r\n            <iteration index=\"44\" Duration=\"7.2928000092506409\" />\r\n            <iteration index=\"45\" Duration=\"7.251800000667572\" />\r\n            <iteration index=\"46\" Duration=\"7.6187999844551086\" />\r\n            <iteration index=\"47\" Duration=\"7.1907999813556671\" />\r\n            <iteration index=\"48\" Duration=\"7.3662000000476837\" />\r\n            <iteration index=\"49\" Duration=\"7.4404000043869019\" />\r\n            <iteration index=\"50\" Duration=\"8.2469000220298767\" />\r\n            <iteration index=\"51\" Duration=\"7.9103000164031982\" />\r\n            <iteration index=\"52\" Duration=\"8.24549999833107\" />\r\n            <iteration index=\"53\" Duration=\"7.9812999963760376\" />\r\n            <iteration index=\"54\" Duration=\"7.9167999923229218\" />\r\n            <iteration index=\"55\" Duration=\"7.5810999870300293\" />\r\n            <iteration index=\"56\" Duration=\"7.500900000333786\" />\r\n            <iteration index=\"57\" Duration=\"7.6854999959468842\" />\r\n            <iteration index=\"58\" Duration=\"7.5491999983787537\" />\r\n            <iteration index=\"59\" Duration=\"7.48199999332428\" />\r\n            <iteration index=\"60\" Duration=\"7.6207999885082245\" />\r\n            <iteration index=\"61\" Duration=\"7.2836000025272369\" />\r\n            <iteration index=\"62\" Duration=\"7.91949999332428\" />\r\n            <iteration index=\"63\" Duration=\"7.2569999992847443\" />\r\n            <iteration index=\"64\" Duration=\"7.6213000118732452\" />\r\n            <iteration index=\"65\" Duration=\"7.5294999778270721\" />\r\n            <iteration index=\"66\" Duration=\"7.5785000026226044\" />\r\n            <iteration index=\"67\" Duration=\"8.1162000000476837\" />\r\n            <iteration index=\"68\" Duration=\"7.5515999794006348\" />\r\n            <iteration index=\"69\" Duration=\"7.550900012254715\" />\r\n            <iteration index=\"70\" Duration=\"7.6274999976158142\" />\r\n            <iteration index=\"71\" Duration=\"10.337799996137619\" />\r\n            <iteration index=\"72\" Duration=\"8.2260999977588654\" />\r\n            <iteration index=\"73\" Duration=\"7.8145999908447266\" />\r\n            <iteration index=\"74\" Duration=\"8.1037000119686127\" />\r\n            <iteration index=\"75\" Duration=\"7.7612999975681305\" />\r\n            <iteration index=\"76\" Duration=\"7.8133000135421753\" />\r\n            <iteration index=\"77\" Duration=\"11.580399990081787\" />\r\n            <iteration index=\"78\" Duration=\"18.271800011396408\" />\r\n            <iteration index=\"79\" Duration=\"18.277200013399124\" />\r\n            <iteration index=\"80\" Duration=\"16.548899978399277\" />\r\n            <iteration index=\"81\" Duration=\"13.923599988222122\" />\r\n            <iteration index=\"82\" Duration=\"8.122299998998642\" />\r\n            <iteration index=\"83\" Duration=\"7.8748000264167786\" />\r\n            <iteration index=\"84\" Duration=\"7.6301999986171722\" />\r\n            <iteration index=\"85\" Duration=\"7.9761999845504761\" />\r\n            <iteration index=\"86\" Duration=\"7.3576000034809113\" />\r\n            <iteration index=\"87\" Duration=\"7.8889999985694885\" />\r\n            <iteration index=\"88\" Duration=\"7.9345999956130981\" />\r\n            <iteration index=\"89\" Duration=\"8.2256999909877777\" />\r\n            <iteration index=\"90\" Duration=\"7.6966999769210815\" />\r\n            <iteration index=\"91\" Duration=\"7.9787000119686127\" />\r\n            <iteration index=\"92\" Duration=\"8.0125000178813934\" />\r\n            <iteration index=\"93\" Duration=\"8.0029000043869019\" />\r\n            <iteration index=\"94\" Duration=\"7.468999981880188\" />\r\n            <iteration index=\"95\" Duration=\"8.4246000051498413\" />\r\n            <iteration index=\"96\" Duration=\"7.4307000041008\" />\r\n            <iteration index=\"97\" Duration=\"7.8256999850273132\" />\r\n            <iteration index=\"98\" Duration=\"7.2653999924659729\" />\r\n            <iteration index=\"99\" Duration=\"7.5108000040054321\" />\r\n            <iteration index=\"100\" Duration=\"7.1114000082015991\" />\r\n          </iterations>\r\n        </performance>\r\n```\r\n\r\nWindows perf results for Dictionary:\r\n```\r\n        <performance runid=\"System.Collections.Tests.Perf_Dictionary.ctor-WindowsCore\" etl=\"D:\\git\\corefx\\bin\\tests\\Windows_NT.AnyCPU.Release\\system.collections.tests\\dnxcore50\\System.Collections.Tests.Perf_Dictionary.ctor-WindowsCore.etl\">\r\n          <metrics>\r\n            <Duration displayName=\"Duration\" unit=\"msec\" />\r\n          </metrics>\r\n          <iterations>\r\n            <iteration index=\"0\" Duration=\"7.4104083850060078\" />\r\n            <iteration index=\"1\" Duration=\"6.5154687143175352\" />\r\n            <iteration index=\"2\" Duration=\"5.9734870915144711\" />\r\n            <iteration index=\"3\" Duration=\"5.4272289172427008\" />\r\n            <iteration index=\"4\" Duration=\"5.3662167829556893\" />\r\n            <iteration index=\"5\" Duration=\"5.5495382892482894\" />\r\n            <iteration index=\"6\" Duration=\"7.149538745413679\" />\r\n            <iteration index=\"7\" Duration=\"5.3214555442496021\" />\r\n            <iteration index=\"8\" Duration=\"5.214256654100268\" />\r\n            <iteration index=\"9\" Duration=\"5.48396450006112\" />\r\n            <iteration index=\"10\" Duration=\"5.2798304432874374\" />\r\n            <iteration index=\"11\" Duration=\"5.4283693309677119\" />\r\n            <iteration index=\"12\" Duration=\"5.340272370712\" />\r\n            <iteration index=\"13\" Duration=\"5.5404149794483146\" />\r\n            <iteration index=\"14\" Duration=\"5.3665018863869136\" />\r\n            <iteration index=\"15\" Duration=\"5.3987185741178791\" />\r\n            <iteration index=\"16\" Duration=\"5.8303651690278\" />\r\n            <iteration index=\"17\" Duration=\"5.443194709392742\" />\r\n            <iteration index=\"18\" Duration=\"5.4229523657739946\" />\r\n            <iteration index=\"19\" Duration=\"5.2179629987065255\" />\r\n            <iteration index=\"20\" Duration=\"5.5837507009980527\" />\r\n            <iteration index=\"21\" Duration=\"5.3234512682682862\" />\r\n            <iteration index=\"22\" Duration=\"6.0490395007952884\" />\r\n            <iteration index=\"23\" Duration=\"5.1267299007071188\" />\r\n            <iteration index=\"24\" Duration=\"4.8732729503271912\" />\r\n            <iteration index=\"25\" Duration=\"4.9767654958703815\" />\r\n            <iteration index=\"26\" Duration=\"4.8627241233710947\" />\r\n            <iteration index=\"27\" Duration=\"4.9576635659767589\" />\r\n            <iteration index=\"28\" Duration=\"4.8761239846397757\" />\r\n            <iteration index=\"29\" Duration=\"5.1632231399067905\" />\r\n            <iteration index=\"30\" Duration=\"4.9362808086331142\" />\r\n            <iteration index=\"31\" Duration=\"5.1019259021884409\" />\r\n            <iteration index=\"32\" Duration=\"4.8986471557084315\" />\r\n            <iteration index=\"33\" Duration=\"5.0962238335634993\" />\r\n            <iteration index=\"34\" Duration=\"4.9200299130520762\" />\r\n            <iteration index=\"35\" Duration=\"5.0451903193700218\" />\r\n            <iteration index=\"36\" Duration=\"5.1757676908816848\" />\r\n            <iteration index=\"37\" Duration=\"4.8644347439586682\" />\r\n            <iteration index=\"38\" Duration=\"5.3140428550370871\" />\r\n            <iteration index=\"39\" Duration=\"4.88695791502721\" />\r\n            <iteration index=\"40\" Duration=\"4.8581624684711642\" />\r\n            <iteration index=\"41\" Duration=\"5.0950834198384882\" />\r\n            <iteration index=\"42\" Duration=\"5.4084120907804163\" />\r\n            <iteration index=\"43\" Duration=\"4.9271574988332532\" />\r\n            <iteration index=\"44\" Duration=\"4.9673570826392961\" />\r\n            <iteration index=\"45\" Duration=\"4.8094097817277088\" />\r\n            <iteration index=\"46\" Duration=\"4.8248053670150739\" />\r\n            <iteration index=\"47\" Duration=\"4.6945130989346353\" />\r\n            <iteration index=\"48\" Duration=\"4.9037790174708107\" />\r\n            <iteration index=\"49\" Duration=\"4.937991429220574\" />\r\n            <iteration index=\"50\" Duration=\"5.0277990100639727\" />\r\n            <iteration index=\"51\" Duration=\"5.0067013561515523\" />\r\n            <iteration index=\"52\" Duration=\"5.0055609424264276\" />\r\n            <iteration index=\"53\" Duration=\"4.819388401821243\" />\r\n            <iteration index=\"54\" Duration=\"4.820813918977592\" />\r\n            <iteration index=\"55\" Duration=\"5.1518190026567936\" />\r\n            <iteration index=\"56\" Duration=\"4.8322180562277026\" />\r\n            <iteration index=\"57\" Duration=\"5.4389181579240358\" />\r\n            <iteration index=\"58\" Duration=\"4.8037077131027672\" />\r\n            <iteration index=\"59\" Duration=\"4.8695666057210474\" />\r\n            <iteration index=\"60\" Duration=\"4.9154682581520319\" />\r\n            <iteration index=\"61\" Duration=\"4.81226081604018\" />\r\n            <iteration index=\"62\" Duration=\"4.9046343277645974\" />\r\n            <iteration index=\"63\" Duration=\"4.9100512929583147\" />\r\n            <iteration index=\"64\" Duration=\"5.1136151428695484\" />\r\n            <iteration index=\"65\" Duration=\"4.8607283993524106\" />\r\n            <iteration index=\"66\" Duration=\"4.8627241233712084\" />\r\n            <iteration index=\"67\" Duration=\"4.8319329527962509\" />\r\n            <iteration index=\"68\" Duration=\"4.972774047833127\" />\r\n            <iteration index=\"69\" Duration=\"4.96935280665798\" />\r\n            <iteration index=\"70\" Duration=\"4.9659315654830607\" />\r\n            <iteration index=\"71\" Duration=\"5.1039216262070113\" />\r\n            <iteration index=\"72\" Duration=\"4.8918046733583651\" />\r\n            <iteration index=\"73\" Duration=\"5.1321468659007223\" />\r\n            <iteration index=\"74\" Duration=\"4.8604432959211863\" />\r\n            <iteration index=\"75\" Duration=\"4.8210990224088164\" />\r\n            <iteration index=\"76\" Duration=\"4.9476849458831111\" />\r\n            <iteration index=\"77\" Duration=\"4.9200299130518488\" />\r\n            <iteration index=\"78\" Duration=\"5.0092672870327988\" />\r\n            <iteration index=\"79\" Duration=\"5.21824810213775\" />\r\n            <iteration index=\"80\" Duration=\"4.9642209448954873\" />\r\n            <iteration index=\"81\" Duration=\"5.1854612075442219\" />\r\n            <iteration index=\"82\" Duration=\"5.9763381258269419\" />\r\n            <iteration index=\"83\" Duration=\"8.7518200290292043\" />\r\n            <iteration index=\"84\" Duration=\"5.3693529206993844\" />\r\n            <iteration index=\"85\" Duration=\"5.1215980389447395\" />\r\n            <iteration index=\"86\" Duration=\"4.8159671606463235\" />\r\n            <iteration index=\"87\" Duration=\"5.334285198655607\" />\r\n            <iteration index=\"88\" Duration=\"4.9314340503019594\" />\r\n            <iteration index=\"89\" Duration=\"4.8843919841460774\" />\r\n            <iteration index=\"90\" Duration=\"5.0477562502512683\" />\r\n            <iteration index=\"91\" Duration=\"4.80883957486526\" />\r\n            <iteration index=\"92\" Duration=\"4.8176777812338969\" />\r\n            <iteration index=\"93\" Duration=\"4.9317191537331837\" />\r\n            <iteration index=\"94\" Duration=\"4.9556678419578475\" />\r\n            <iteration index=\"95\" Duration=\"4.7272999935282769\" />\r\n            <iteration index=\"96\" Duration=\"4.8228096429961624\" />\r\n            <iteration index=\"97\" Duration=\"4.8698517091522717\" />\r\n            <iteration index=\"98\" Duration=\"4.764933646452846\" />\r\n            <iteration index=\"99\" Duration=\"5.172916656569214\" />\r\n            <iteration index=\"100\" Duration=\"5.3967228500991951\" />\r\n          </iterations>\r\n        </performance>\r\n```\r\n\r\n\r\nLinux perf results for List:\r\n```\r\n        <performance runid=\"System.Collections.Tests.Perf_List.ctor-Linux\" etl=\"/home/ianha/uptonogood/results/System.Collections.Tests.Perf_List.ctor-Linux.csv\">\r\n          <metrics>\r\n            <Duration displayName=\"Duration\" unit=\"msec\" />\r\n          </metrics>\r\n          <iterations>\r\n            <iteration index=\"0\" Duration=\"12.166699975728989\" />\r\n            <iteration index=\"1\" Duration=\"10.878299981355667\" />\r\n            <iteration index=\"2\" Duration=\"10.500300019979477\" />\r\n            <iteration index=\"3\" Duration=\"10.475400000810623\" />\r\n            <iteration index=\"4\" Duration=\"10.260699987411499\" />\r\n            <iteration index=\"5\" Duration=\"11.584399998188019\" />\r\n            <iteration index=\"6\" Duration=\"10.057400017976761\" />\r\n            <iteration index=\"7\" Duration=\"10.019500017166138\" />\r\n            <iteration index=\"8\" Duration=\"9.9130000174045563\" />\r\n            <iteration index=\"9\" Duration=\"10.055099993944168\" />\r\n            <iteration index=\"10\" Duration=\"9.9984000027179718\" />\r\n            <iteration index=\"11\" Duration=\"10.008300006389618\" />\r\n            <iteration index=\"12\" Duration=\"10.21560001373291\" />\r\n            <iteration index=\"13\" Duration=\"9.9362000226974487\" />\r\n            <iteration index=\"14\" Duration=\"9.9869000017642975\" />\r\n            <iteration index=\"15\" Duration=\"10.00789999961853\" />\r\n            <iteration index=\"16\" Duration=\"9.9068999886512756\" />\r\n            <iteration index=\"17\" Duration=\"10.542999982833862\" />\r\n            <iteration index=\"18\" Duration=\"10.169900000095367\" />\r\n            <iteration index=\"19\" Duration=\"10.178999990224838\" />\r\n            <iteration index=\"20\" Duration=\"10.347100019454956\" />\r\n            <iteration index=\"21\" Duration=\"10.062999993562698\" />\r\n            <iteration index=\"22\" Duration=\"10.074499994516373\" />\r\n            <iteration index=\"23\" Duration=\"11.727899998426437\" />\r\n            <iteration index=\"24\" Duration=\"10.298799991607666\" />\r\n            <iteration index=\"25\" Duration=\"10.154199987649918\" />\r\n            <iteration index=\"26\" Duration=\"15.834300011396408\" />\r\n            <iteration index=\"27\" Duration=\"17.311800003051758\" />\r\n            <iteration index=\"28\" Duration=\"17.555900007486343\" />\r\n            <iteration index=\"29\" Duration=\"19.215399980545044\" />\r\n            <iteration index=\"30\" Duration=\"10.369499981403351\" />\r\n            <iteration index=\"31\" Duration=\"10.304100006818771\" />\r\n            <iteration index=\"32\" Duration=\"10.445600003004074\" />\r\n            <iteration index=\"33\" Duration=\"10.526000022888184\" />\r\n            <iteration index=\"34\" Duration=\"10.229199975728989\" />\r\n            <iteration index=\"35\" Duration=\"10.707199990749359\" />\r\n            <iteration index=\"36\" Duration=\"10.149199992418289\" />\r\n            <iteration index=\"37\" Duration=\"10.130699992179871\" />\r\n            <iteration index=\"38\" Duration=\"10.592200011014938\" />\r\n            <iteration index=\"39\" Duration=\"10.47749999165535\" />\r\n            <iteration index=\"40\" Duration=\"10.475899994373322\" />\r\n            <iteration index=\"41\" Duration=\"10.383599996566772\" />\r\n            <iteration index=\"42\" Duration=\"10.223899990320206\" />\r\n            <iteration index=\"43\" Duration=\"10.168499976396561\" />\r\n            <iteration index=\"44\" Duration=\"10.540100008249283\" />\r\n            <iteration index=\"45\" Duration=\"10.747299998998642\" />\r\n            <iteration index=\"46\" Duration=\"10.224299997091293\" />\r\n            <iteration index=\"47\" Duration=\"10.199999988079071\" />\r\n            <iteration index=\"48\" Duration=\"14.77700001001358\" />\r\n            <iteration index=\"49\" Duration=\"15.136800020933151\" />\r\n            <iteration index=\"50\" Duration=\"18.946599990129471\" />\r\n            <iteration index=\"51\" Duration=\"14.777700006961823\" />\r\n            <iteration index=\"52\" Duration=\"11.193500012159348\" />\r\n            <iteration index=\"53\" Duration=\"10.182099997997284\" />\r\n            <iteration index=\"54\" Duration=\"10.395599991083145\" />\r\n            <iteration index=\"55\" Duration=\"10.344199985265732\" />\r\n            <iteration index=\"56\" Duration=\"10.175599992275238\" />\r\n            <iteration index=\"57\" Duration=\"9.9704000055789948\" />\r\n            <iteration index=\"58\" Duration=\"10.066700011491776\" />\r\n            <iteration index=\"59\" Duration=\"10.239700019359589\" />\r\n            <iteration index=\"60\" Duration=\"11.068599998950958\" />\r\n            <iteration index=\"61\" Duration=\"10.008399993181229\" />\r\n            <iteration index=\"62\" Duration=\"9.962799996137619\" />\r\n            <iteration index=\"63\" Duration=\"10.357299983501434\" />\r\n            <iteration index=\"64\" Duration=\"10.018399983644485\" />\r\n            <iteration index=\"65\" Duration=\"10.000699996948242\" />\r\n            <iteration index=\"66\" Duration=\"10.357600003480911\" />\r\n            <iteration index=\"67\" Duration=\"10.061700016260147\" />\r\n            <iteration index=\"68\" Duration=\"9.9657999873161316\" />\r\n            <iteration index=\"69\" Duration=\"10.020999997854233\" />\r\n            <iteration index=\"70\" Duration=\"10.035899996757507\" />\r\n            <iteration index=\"71\" Duration=\"10.014100015163422\" />\r\n            <iteration index=\"72\" Duration=\"10.103100001811981\" />\r\n            <iteration index=\"73\" Duration=\"10.140599995851517\" />\r\n            <iteration index=\"74\" Duration=\"9.97969999909401\" />\r\n            <iteration index=\"75\" Duration=\"10.17969998717308\" />\r\n            <iteration index=\"76\" Duration=\"10.084699988365173\" />\r\n            <iteration index=\"77\" Duration=\"10.123600006103516\" />\r\n            <iteration index=\"78\" Duration=\"9.960099995136261\" />\r\n            <iteration index=\"79\" Duration=\"10.484499990940094\" />\r\n            <iteration index=\"80\" Duration=\"10.156100004911423\" />\r\n            <iteration index=\"81\" Duration=\"10.909199982881546\" />\r\n            <iteration index=\"82\" Duration=\"16.772300004959106\" />\r\n            <iteration index=\"83\" Duration=\"14.837800025939941\" />\r\n            <iteration index=\"84\" Duration=\"15.056299984455109\" />\r\n            <iteration index=\"85\" Duration=\"25.050500005483627\" />\r\n            <iteration index=\"86\" Duration=\"15.694700002670288\" />\r\n          </iterations>\r\n        </performance>\r\n```\r\n\r\nWindows perf results for List<object>\r\n```\r\n        <performance runid=\"System.Collections.Tests.Perf_List.ctor-WindowsCore\" etl=\"D:\\git\\corefx\\bin\\tests\\Windows_NT.AnyCPU.Release\\system.collections.tests\\dnxcore50\\System.Collections.Tests.Perf_List.ctor-WindowsCore.etl\">\r\n          <metrics>\r\n            <Duration displayName=\"Duration\" unit=\"msec\" />\r\n          </metrics>\r\n          <iterations>\r\n            <iteration index=\"0\" Duration=\"3.3502504205988544\" />\r\n            <iteration index=\"1\" Duration=\"2.2990740695863678\" />\r\n            <iteration index=\"2\" Duration=\"1.9632222275758977\" />\r\n            <iteration index=\"3\" Duration=\"1.9623669172819973\" />\r\n            <iteration index=\"4\" Duration=\"1.9848900883507667\" />\r\n            <iteration index=\"5\" Duration=\"1.9669285721820415\" />\r\n            <iteration index=\"6\" Duration=\"1.9595158829696402\" />\r\n            <iteration index=\"7\" Duration=\"1.8756954741826348\" />\r\n            <iteration index=\"8\" Duration=\"2.1465437338684978\" />\r\n            <iteration index=\"9\" Duration=\"1.9942985015818522\" />\r\n            <iteration index=\"10\" Duration=\"2.0285109133316155\" />\r\n            <iteration index=\"11\" Duration=\"1.9826092609007446\" />\r\n            <iteration index=\"12\" Duration=\"1.970349813356961\" />\r\n            <iteration index=\"13\" Duration=\"1.956094641794607\" />\r\n            <iteration index=\"14\" Duration=\"1.8722742330077153\" />\r\n            <iteration index=\"15\" Duration=\"2.0014260873631429\" />\r\n            <iteration index=\"16\" Duration=\"2.2189600054055063\" />\r\n            <iteration index=\"17\" Duration=\"2.0151110520630482\" />\r\n            <iteration index=\"18\" Duration=\"1.9866007089382265\" />\r\n            <iteration index=\"19\" Duration=\"1.9612265035571\" />\r\n            <iteration index=\"20\" Duration=\"1.9689242962008393\" />\r\n            <iteration index=\"21\" Duration=\"1.8774060947700946\" />\r\n            <iteration index=\"22\" Duration=\"2.038489533425377\" />\r\n            <iteration index=\"23\" Duration=\"2.0287960167629535\" />\r\n            <iteration index=\"24\" Duration=\"2.1414118721060049\" />\r\n            <iteration index=\"25\" Duration=\"2.2018537995306815\" />\r\n            <iteration index=\"26\" Duration=\"2.0430511883254212\" />\r\n            <iteration index=\"27\" Duration=\"2.0239492584316849\" />\r\n            <iteration index=\"28\" Duration=\"1.8640062335014136\" />\r\n            <iteration index=\"29\" Duration=\"1.98403477805698\" />\r\n            <iteration index=\"30\" Duration=\"1.9871709158006752\" />\r\n            <iteration index=\"31\" Duration=\"2.1160376667248784\" />\r\n            <iteration index=\"32\" Duration=\"2.2183897985430576\" />\r\n            <iteration index=\"33\" Duration=\"2.2474703485304417\" />\r\n            <iteration index=\"34\" Duration=\"2.1268715971123129\" />\r\n            <iteration index=\"35\" Duration=\"1.8805422325137897\" />\r\n            <iteration index=\"36\" Duration=\"1.9777625025694761\" />\r\n            <iteration index=\"37\" Duration=\"1.9703498133570747\" />\r\n            <iteration index=\"38\" Duration=\"1.9692093996320637\" />\r\n            <iteration index=\"39\" Duration=\"2.2400576593179267\" />\r\n            <iteration index=\"40\" Duration=\"2.0325023613690973\" />\r\n            <iteration index=\"41\" Duration=\"2.0746976691939381\" />\r\n            <iteration index=\"42\" Duration=\"2.032217257937873\" />\r\n            <iteration index=\"43\" Duration=\"1.9985750530505584\" />\r\n            <iteration index=\"44\" Duration=\"1.97177533051331\" />\r\n            <iteration index=\"45\" Duration=\"2.011689810888015\" />\r\n            <iteration index=\"46\" Duration=\"2.0051324319692867\" />\r\n            <iteration index=\"47\" Duration=\"2.0114047074567907\" />\r\n            <iteration index=\"48\" Duration=\"2.0122600177505774\" />\r\n            <iteration index=\"49\" Duration=\"1.9655030550258061\" />\r\n            <iteration index=\"50\" Duration=\"1.9119036099511959\" />\r\n            <iteration index=\"51\" Duration=\"2.164220146605885\" />\r\n            <iteration index=\"52\" Duration=\"1.9751965716882296\" />\r\n            <iteration index=\"53\" Duration=\"1.9942985015818522\" />\r\n            <iteration index=\"54\" Duration=\"2.0076983628505332\" />\r\n            <iteration index=\"55\" Duration=\"2.0615829113564814\" />\r\n            <iteration index=\"56\" Duration=\"2.017962086375519\" />\r\n            <iteration index=\"57\" Duration=\"1.9002143692699747\" />\r\n            <iteration index=\"58\" Duration=\"2.0795444275250929\" />\r\n            <iteration index=\"59\" Duration=\"1.9677838824758282\" />\r\n            <iteration index=\"60\" Duration=\"2.0878124270313947\" />\r\n            <iteration index=\"61\" Duration=\"2.0387746368566013\" />\r\n            <iteration index=\"62\" Duration=\"1.962366917282111\" />\r\n            <iteration index=\"63\" Duration=\"1.9669285721820415\" />\r\n            <iteration index=\"64\" Duration=\"1.8258023737141684\" />\r\n            <iteration index=\"65\" Duration=\"1.9814688471757336\" />\r\n            <iteration index=\"66\" Duration=\"2.0692807040002208\" />\r\n            <iteration index=\"67\" Duration=\"2.02081312068799\" />\r\n            <iteration index=\"68\" Duration=\"2.0327874648004354\" />\r\n            <iteration index=\"69\" Duration=\"2.20670055786195\" />\r\n            <iteration index=\"70\" Duration=\"1.9806135368819469\" />\r\n            <iteration index=\"71\" Duration=\"1.9113334030886335\" />\r\n            <iteration index=\"72\" Duration=\"2.0094089834379929\" />\r\n            <iteration index=\"73\" Duration=\"2.0076983628505332\" />\r\n            <iteration index=\"74\" Duration=\"1.9737710545319942\" />\r\n            <iteration index=\"75\" Duration=\"2.0216684309816628\" />\r\n            <iteration index=\"76\" Duration=\"1.9640775378695707\" />\r\n            <iteration index=\"77\" Duration=\"2.0835358755626885\" />\r\n            <iteration index=\"78\" Duration=\"2.0878124270313947\" />\r\n            <iteration index=\"79\" Duration=\"1.8526020962514167\" />\r\n            <iteration index=\"80\" Duration=\"1.9672136756132659\" />\r\n            <iteration index=\"81\" Duration=\"1.9081972653449384\" />\r\n            <iteration index=\"82\" Duration=\"2.0575914633189996\" />\r\n            <iteration index=\"83\" Duration=\"2.02081312068799\" />\r\n            <iteration index=\"84\" Duration=\"1.9481117457196433\" />\r\n            <iteration index=\"85\" Duration=\"2.0316470510754243\" />\r\n            <iteration index=\"86\" Duration=\"1.948111745719757\" />\r\n            <iteration index=\"87\" Duration=\"1.9737710545319942\" />\r\n            <iteration index=\"88\" Duration=\"1.8956527143699304\" />\r\n            <iteration index=\"89\" Duration=\"2.0721317383126916\" />\r\n            <iteration index=\"90\" Duration=\"1.9709200202195234\" />\r\n            <iteration index=\"91\" Duration=\"2.2354960044179961\" />\r\n            <iteration index=\"92\" Duration=\"2.1761944907183306\" />\r\n            <iteration index=\"93\" Duration=\"2.0501787741065982\" />\r\n            <iteration index=\"94\" Duration=\"2.1972921446306373\" />\r\n            <iteration index=\"95\" Duration=\"2.1767646975807793\" />\r\n            <iteration index=\"96\" Duration=\"2.1590882848433921\" />\r\n            <iteration index=\"97\" Duration=\"2.2734147607740169\" />\r\n            <iteration index=\"98\" Duration=\"2.2032793166868032\" />\r\n            <iteration index=\"99\" Duration=\"2.2055601441368253\" />\r\n            <iteration index=\"100\" Duration=\"2.0490383603815872\" />\r\n          </iterations>\r\n        </performance>\r\n```\r\n\r\nNote that these results are only for the default constructors. Results for ```new Dictionary(int size)```, ```new List(int size)```, and ```new List(IEnumerable enumerable)``` are even across platforms. I suspect we would get similar results for other collections, but I have yet to add tests for any other generic collections\r\n\r\nConfirmed these results with the old-fashioned Stopwatch-around-the-iteration-loop method."}}