![\"\"](\"http:\/\/knownshippable.com\/blog\/wp-content\/uploads\/2017\/03\/home_timings.png\")
<\/p>\nCaching is\u00a0a key feature in FASTBuild that allows machines to share the result of previous builds with each other avoiding unnecessary recompilation of the same code and resulting in a drastic total build time reduction. If you are familiar with ccache… this may sound like old news!<\/p>\n
In a typical scenario we\u00a0can imagine a central build machine that continuously builds a project and writes the result changed object files into the shared cache. Later when the team members\u00a0need to re-compile that same version\u00a0of the source\u00a0files, instead of recompiling them FASTBuild will detect the cache-hits and transfer the cached results which can be is significantly faster.<\/p>\n
Here is an example of build times both with and without the FASTBuild caching feature from the FASTBuild website:<\/p>\n
<\/p>\n
Note that the build caching is not offered\u00a0on commercial products like Incredibuild, making it a unique feature to FASTBuild!<\/p>\n
The setup is straightforward and consists of\u00a03 steps:<\/p>\n
1) Create a\u00a0shared cache folder.<\/p>\n
2) Set\u00a0the CachePath attribute\u00a0in the Unreal\u00a0FastBuild.cs<\/a>\u00a0to the network location selected\u00a0in step 1).<\/p>\n 3) Launch a new build and observe the cache folder being populated.<\/p>\n Assuming we\u2019re running on Windows, here are a few more details about each step:<\/p>\n a) Choose\u00a0a computer that is available on the local network, i.e. it is accessible by all computers participating in the build.<\/p>\n b) Create a new folder named something like\u00a0FASTBuild<\/strong>Shared<\/strong>. This folder will contain all FASTBuild shared files. Enable Windows sharing on that folder.<\/p>\n c) Make sure to give Read\/Write permissions to all users\/machines that need to access the central cache.<\/p>\n d) Create a sub-folder called Cache<\/strong>, this will contain our FASTBuild cache structure.<\/p>\n Tips and Troubleshooting:<\/p>\n There are 2 ways of specifying the cache location:<\/p>\n a) Local option: Through the Unreal FastBuild.cs<\/a> options:<\/p>\n You can simply edit the CachePath<\/strong>\u00a0attribute\u00a0and specify the network location created in step 1).<\/p>\n b) Global option: Through system environment variables:<\/p>\n Open the Windows Environment Variables Settings (System->Advanced system settings->Environment Variables) and add a new entry called\u00a0FASTBUILD_CACHE_PATH<\/strong>.<\/strong> The value needs to be set to the network location created in step 1).<\/p>\n In our example:\u00a0\\\\DESKTOP-BEAST\\FastBuildShared\\Cache<\/strong><\/p>\n Now that we have created the central shared cache in Step 1 and configured\u00a0its location on every build client in Step 2, we can start a new build.<\/p>\n If everything is OK you should see the cache structure being gradually populated with directories and files:<\/p>\n After\u00a0the first build is completed, try to rebuild the same code once again and you should notice that the build client is able to retrieve build results from the cache. In the Visual Studio output window you should start seeing logs that look like:<\/p>\n 5> \u00a04> Obj: D:\\Dev-Projects\\Unreal4\\UnrealTournament\\Engine\\Intermediate\\Build\\Win64\\UE4\\Development\\MediaAssets\\Module.MediaAssets.cpp.obj <CACHE<\/strong><\/span>><\/p>\n The FASTBuild Summary is useful to inspect how the cache performed in the last build session:<\/p>\n Tips:<\/p>\n How it works Caching is\u00a0a key feature in FASTBuild that allows machines to share the result of previous builds with each other avoiding unnecessary recompilation of the same code and resulting in a drastic total build time reduction. If you are familiar with ccache… this may sound like old news! In a typical scenario we\u00a0can … Continue reading “FASTBuild Caching setup”<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,3],"tags":[],"class_list":["post-29","post","type-post","status-publish","format-standard","hentry","category-fastbuild","category-unreal-engine"],"_links":{"self":[{"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/posts\/29","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/comments?post=29"}],"version-history":[{"count":10,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/posts\/29\/revisions"}],"predecessor-version":[{"id":100,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/posts\/29\/revisions\/100"}],"wp:attachment":[{"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/media?parent=29"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/categories?post=29"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/knownshippable.com\/blog\/wp-json\/wp\/v2\/tags?post=29"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}1. Create the\u00a0shared cache location:<\/h5>\n
![\"FBuild-Cache-Sharing\"](\"http:\/\/knownshippable.com\/blog\/wp-content\/uploads\/2016\/08\/FBuild-Cache-Sharing.png\")
<\/p>\n\n
2. Specify the cache location on the build\u00a0clients:<\/h5>\n
\nprivate static string CachePath = \"\\\\\\\\DESKTOP-BEAST\\\\FastBuildShared\\\\Cache\"; \/\/ Optional: Location of the FASTBuild shared cache (local or network location).\n<\/pre>\n
3. Build with the FASTBuild cache enabled:<\/h5>\n
![\"FBuild-Cache-directory\"](\"http:\/\/knownshippable.com\/blog\/wp-content\/uploads\/2016\/08\/FBuild-Cache-directory.png\")
<\/p>\n![\"FBuild-Cache-VSOutput\"](\"http:\/\/knownshippable.com\/blog\/wp-content\/uploads\/2016\/08\/FBuild-Cache-VSOutput.png\")
<\/p>\n\n