|author||Dan Willemsen <email@example.com>||Thu Apr 05 15:25:59 2018 -0700|
|committer||Dan Willemsen <firstname.lastname@example.org>||Thu Apr 05 15:25:59 2018 -0700|
Remove our binary of ccache Our binary was rather old, and for a variety of reasons we haven't kept it updated. We've been running into a handful of reliability issues that would have been fixed with an update, and a few reproducibility / correctness issues that may or may not be fixed with newer versions. For local no-change full rebuilds, ccache can still save ~35% of the build time (but adds a few minutes to initially populate the cache). But most local uses should be using incremental builds anyways, not clean rebuilds. Or you're doing builds of different configurations, which wouldn't be cache hits either, and would make your cache even larger. At a large scale, we haven't seen a significant performance difference between having ccache on or off. This may be different if you've got very good build locality, or a very large cache -- but if you've got good build locality, it's reasonable to do incremental builds (not for release builds, and while running `m installclean` in between builds). So for our cases, we'd prefer the stability and correctness of not using ccache, but if you still want to use ccache, continue setting USE_CCACHE and also set CCACHE_EXEC to the path of your ccache executable. Bug: 32748498 Bug: 72408185 Test: performance testing of USE_CCACHE=false vs true locally Test: turned off ccache for a collection of targets Test: CCACHE_EXEC=/usr/bin/ccache USE_CCACHE=true m Change-Id: I7117fe3107bd98521051ae343038a38f7e855502
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