dotnet core 2由于恢复时间长，构建时间长 [英] dotnet core 2 long build time because of long restore time
问题描述
我注意到在dotnet core 2中构建似乎要慢得多.
但是构建后的时间总是显示仅" 15秒.
我简直不敢相信，所以我给它定了time.
I noticed that building in dotnet core 2 seemed a lot slower.
But the timing after the build always showed 'only' 15 seconds.
I couldn't believe that so I timed it with time.
> 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，我尝试不进行还原，并且速度更快:
That seemed more correct. Almost a minute.
I then tried without restore and it was a lot faster:
> 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15秒.
难道只有建筑才算在时间里?
不确定为什么所有内容都已还原后，还原总是很慢.
But dotnet also shows 15 seconds.
Could it be that only building is counted in the timings?
Not sure why a restore is always slow when everything is already restored.
还有其他方法可以加快构建过程吗?禁用遥测? (我正在使用osx，我的环境已设置为开发状态)
Are there other ways I could speed up the building process? Disable telemetry? (I'm using osx, my environment is set to development)
我更喜欢使用dotnet watch run，但这似乎更慢.
运行dotnet watch来查看参数需要12秒钟.
I prefer to use dotnet watch run but that seems even slower.
Running dotnet watch to view the parameters is taking 12 seconds.
> 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
这仅在我的系统上吗?
更新:
这是dotnet restore/clp:PerformanceSummary的结果
Here is the result from dotnet restore /clp:PerformanceSummary
> 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
推荐答案
长话短说:MSBuild根据所用SDK定义的glob模式扫描整个文件夹结构.每个项目评估都完成了此操作，NuGet还原似乎至少触发了三个完整评估.
Long story short: MSBuild scans the entire folder structure based on glob patterns defined by the SDK used. This is done for each project evaluation and the NuGet restore seems to trigger at least three full evaluations.
由于扫描大型目录的速度较慢，因此SDK定义了遍历模式，用于排除一些通常不希望作为项目一部分的已知大型目录(node_modules，bower_components等).
Since it is slow to scan large directories, the SDKs define globbing patterns used to exclude some known large directories that are usually not wanted as part of the project anyway (node_modules, bower_components etc.).
众所周知，特殊情况可能会绕过这些优化，甚至会在包含/排除glob模式扩展/匹配中触发性能错误.
It has been known that special circumstances may circumvent these optimisations and or even trigger performance bugs in the include/exclude glob pattern expansion / matching.
作为预防措施，将所有已知要排除的文件夹添加到DefaultItemExcludes属性(在<PropertyGroup>元素内部):
As a precaution, add all folders known to be excluded to the DefaultItemExcludes property (inside of a <PropertyGroup> element):
<DefaultItemExcludes>custom\node_modules\**;$(DefaultItemExcludes)</DefaultItemExcludes>
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