启用 sccache
在您的项目中启用 Sccache
简介
Sccache 类似于 ccache，它允许缓存构建工件，以便在重新构建时，如果源代码没有更改，则可以从缓存中访问它们。在某些情况下，这可以将重新构建时间缩短超过 85%，从而为您节省时间，允许更多作业在 OBS/IBS 中进行，并节省构建农场的能源。
Sccache 支持缓存 C、C++ 和 Rust，使其成为 ccache 的“即插即用”替代品。但是，您必须小心确保在使用时环境变量和路径相同，否则 sccache 无法正常工作。
要在 sccache 中启用此支持，您需要编辑您的项目配置（而不是软件包配置）。
CLI (osc)
您可以使用以下命令执行此操作
osc meta prjconf <name of project> -e
在其中，您需要指定缓存类型以及应用此配置的软件包名称。
BuildFlags: ccachetype:sccache BuildFlags: useccache:<package name> # if the package uses multibuild you need to specify the flavors BuildFlags: useccache:<package name>:<multibuild flavor>
您可以多次指定 useccache。例如，要将其应用于 kanidm 和 nss_synth 项目，配置如下所示
BuildFlags: ccachetype:sccache BuildFlags: useccache:kanidm BuildFlags: useccache:nss_synth
Webui
导航到您的项目页面并选择“项目配置”。然后，您可以指定与 CLI 相同的构建标志。
检查是否有效
您可以通过检查您的构建日志来查看它是否有效。如果有效，您应该在构建开始时看到
[ 27s] Unpacking sccache archive [ 28s] Compile requests 0 [ 28s] Compile requests executed 0 [ 28s] Cache hits 0 [ 28s] Cache misses 0 [ 28s] Cache timeouts 0 [ 28s] Cache read errors 0 [ 28s] Forced recaches 0 [ 28s] Cache write errors 0 [ 28s] Compilation failures 0 [ 28s] Cache errors 0 [ 28s] Non-cacheable compilations 0 [ 28s] Non-cacheable calls 0 [ 28s] Non-compilation calls 0 [ 28s] Unsupported compiler calls 0 [ 28s] Average cache write 0.000 s [ 28s] Average cache read miss 0.000 s [ 28s] Average cache read hit 0.000 s [ 28s] Failed distributed compilations 0 [ 28s] Cache location Local disk: "/.sccache" [ 28s] Cache size 177 MiB [ 28s] Max cache size 1 GiB
在构建结束时，您将看到有关缓存效果的统计信息。
[ 621s] Compile requests 963 [ 621s] Compile requests executed 680 [ 621s] Cache hits 13 [ 621s] Cache hits (C/C++) 13 [ 621s] Cache misses 660 [ 621s] Cache misses (C/C++) 516 [ 621s] Cache misses (Rust) 144 [ 621s] Cache timeouts 0 [ 621s] Cache read errors 0 [ 621s] Forced recaches 0 [ 621s] Cache write errors 0 [ 621s] Compilation failures 5 [ 621s] Cache errors 2 [ 621s] Cache errors (C/C++) 2 [ 621s] Non-cacheable compilations 0 [ 621s] Non-cacheable calls 114 [ 621s] Non-compilation calls 169 [ 621s] Unsupported compiler calls 0 [ 621s] Average cache write 0.001 s [ 621s] Average cache read miss 1.157 s [ 621s] Average cache read hit 0.000 s [ 621s] Failed distributed compilations 0 [ 621s] [ 621s] Non-cacheable reasons: [ 621s] crate-type 51 [ 621s] -E 32 [ 621s] - 21 [ 621s] argument parse 10 [ 621s] [ 621s] Cache location Local disk: "/.sccache" [ 621s] Cache size 149 MiB [ 621s] Max cache size 1 GiB
这是来自“初始”构建的，因此我们可以看到缓存缺失“很高”。如果我们重新构建，缓存将生效，我们可以在统计信息中看到这一点。如果您在重新构建时经常看到缓存缺失，这可能表明您的环境变量正在发生变化。您可以使用 percent 构建阶段中的“env”命令来转储这些变量进行调查。
一个热构建应该如下所示
[ 249s] Compile requests 963 [ 249s] Compile requests executed 680 [ 249s] Cache hits 673 [ 249s] Cache hits (C/C++) 529 [ 249s] Cache hits (Rust) 144 [ 249s] Cache misses 0 [ 249s] Cache timeouts 0 [ 249s] Cache read errors 0 [ 249s] Forced recaches 0 [ 249s] Cache write errors 0 [ 249s] Compilation failures 5 [ 249s] Cache errors 2 [ 249s] Cache errors (C/C++) 2 [ 249s] Non-cacheable compilations 0 [ 249s] Non-cacheable calls 114 [ 249s] Non-compilation calls 169 [ 249s] Unsupported compiler calls 0 [ 249s] Average cache write 0.000 s [ 249s] Average cache read miss 0.000 s [ 249s] Average cache read hit 0.002 s [ 249s] Failed distributed compilations 0 [ 249s] [ 249s] Non-cacheable reasons: [ 249s] crate-type 51 [ 249s] -E 32 [ 249s] - 21 [ 249s] argument parse 10 [ 249s] [ 249s] Cache location Local disk: "/.sccache" [ 249s] Cache size 149 MiB [ 249s] Max cache size 1 GiB
我们还可以看到执行时间的差异（621s 冷 vs 249s 热）