Question

我注意到在dotnet core 2中构建的速度似乎要慢得多但是，构建之后的时间总是只显示出＃39; 15秒我无法相信，所以我用time计时。

> time dotnet build
Microsoft (R) Build Engine version 15.3.409.57025 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  hrm -> /Users/r/dev/hrm/bin/Debug/netcoreapp2.0/hrm.dll

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:15.45

real    0m52.366s
user    0m36.851s
sys     0m15.458s

这似乎更正确。差不多一分钟然后我试着没有恢复，而且速度要快得多：

> time dotnet build --no-restore
Microsoft (R) Build Engine version 15.3.409.57025 for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

  hrm -> /Users/r/dev/hrm/bin/Debug/netcoreapp2.0/hrm.dll

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:15.39

real    0m15.795s
user    0m11.397s
sys     0m4.238s

但是，dotnet也显示了15秒难道只有建筑才算在时间上了吗？不确定为什么在所有内容都已恢复后恢复总是很慢。

我还有其他方法可以加快建设过程吗？禁用遥测？（我使用osx，我的环境设置为开发）

我更喜欢使用dotnet watch run，但这似乎更慢。运行dotnet watch以查看参数需要12秒。

> time dotnet watch
Microsoft DotNet File Watcher 2.0.0-rtm-26452

Usage: dotnet watch [options] [[--] <arg>...]

Options:
  ....


real    0m12.631s
user    0m8.880s
sys     0m3.816s

这仅限于我的系统吗？

更新

以下是dotnet restore / clp：PerformanceSummary

的结果

> dotnet restore /clp:PerformanceSummary
  Restore completed in 43.95 ms for /Users/roeland/dev/hrm/hrm.csproj.
  Restore completed in 52.73 ms for /Users/roeland/dev/hrm/hrm.csproj.
  Restore completed in 38.48 ms for /Users/roeland/dev/hrm/hrm.csproj.

Project Evaluation Performance Summary:
    36252 ms  /Users/roeland/dev/hrm/hrm.csproj          3 calls

Project Performance Summary:
    36424 ms  /Users/roeland/dev/hrm/hrm.csproj          9 calls
              24359 ms  Restore                                    1 calls
                  1 ms  _IsProjectRestoreSupported                 2 calls
              12011 ms  _GenerateRestoreProjectPathWalk            1 calls
                  1 ms  _GenerateRestoreProjectPathItemsPerFramework   1 calls
                 43 ms  _GenerateRestoreGraphProjectEntry          1 calls
                  0 ms  _GetRestoreSettingsPerFramework            1 calls
                  6 ms  _GenerateProjectRestoreGraph               1 calls
                  3 ms  _GenerateProjectRestoreGraphPerFramework   1 calls

Target Performance Summary:
        0 ms  _GenerateRestoreGraphProjectEntry          1 calls
        0 ms  _GenerateProjectRestoreGraph               1 calls
        0 ms  _GetRestoreTargetFrameworksAsItems         1 calls
        0 ms  _GetRestoreProjectStyle                    2 calls
        0 ms  CheckForImplicitPackageReferenceOverridesBeforeRestore   2 calls
        0 ms  _CheckForUnsupportedNETCoreVersion         1 calls
        0 ms  _IsProjectRestoreSupported                 1 calls
        0 ms  _GetRestoreSettingsPerFramework            1 calls
        0 ms  _GetProjectJsonPath                        2 calls
        0 ms  _GetRestoreSettingsOverrides               1 calls
        1 ms  _GenerateRestoreProjectPathWalk            1 calls
        1 ms  _GenerateRestoreProjectPathItemsPerFramework   1 calls
        1 ms  _GenerateRestoreSpecs                      1 calls
        1 ms  _GenerateRestoreProjectSpec                1 calls
        2 ms  _GenerateProjectRestoreGraphPerFramework   1 calls
        2 ms  _GetRestoreTargetFrameworksOutput          1 calls
        5 ms  _GenerateRestoreDependencies               1 calls
       10 ms  _LoadRestoreGraphEntryPoints               1 calls
       20 ms  _GenerateDotnetCliToolReferenceSpecs       1 calls
       21 ms  _GetRestoreSettings                        1 calls
       54 ms  _GenerateRestoreGraph                      1 calls
      216 ms  Restore                                    1 calls
    12007 ms  _GenerateRestoreProjectPathItems           1 calls
    12014 ms  _GetAllRestoreProjectPathItems             1 calls
    12058 ms  _FilterRestoreGraphProjectInputItems       1 calls

Task Performance Summary:
        1 ms  Message                                    3 calls
        1 ms  ConvertToAbsolutePath                      2 calls
        1 ms  GetRestorePackageReferencesTask            1 calls
        1 ms  GetRestoreProjectReferencesTask            1 calls
        2 ms  GetRestoreProjectFrameworks                1 calls
        3 ms  RemoveDuplicates                           5 calls
        4 ms  WarnForInvalidProjectsTask                 1 calls
       18 ms  GetRestoreSettingsTask                     1 calls
       20 ms  GetRestoreDotnetCliToolsTask               1 calls
      216 ms  RestoreTask                                1 calls
    36121 ms  MsBuild                                    9 calls

Answer 1

长话短说：MSBuild基于所使用的SDK定义的glob模式扫描整个文件夹结构。这是针对每个项目评估完成的，NuGet恢复似乎至少会触发三次完整评估。

由于扫描大目录的速度很慢，因此SDK会定义用于排除一些通常不想作为项目一部分的已知大型目录的通用模式（node_modules，bower_components等）

众所周知，特殊情况可能会绕过这些优化，甚至触发包含/排除glob模式扩展/匹配中的性能错误。

作为预防措施，将已知要排除的所有文件夹添加到DefaultItemExcludes属性中（在<PropertyGroup>元素内）：

<DefaultItemExcludes>custom\node_modules\**;$(DefaultItemExcludes)</DefaultItemExcludes>

Answer 2

对于我来说，exclude.git文件夹有助于使构建速度提高约10倍。

  <PropertyGroup>
    <DefaultItemExcludes>.git\**;$(DefaultItemExcludes)</DefaultItemExcludes>
  </PropertyGroup>

dotnet core 2漫长的构建时间，因为恢复时间很长

2 个答案: