Yes, 1.5hr is the clear build time in my company, it is used in CI daily build, dev build and Gerrit-trigger build. Just want to clarify with you the actual meaning of "incremental build" you mentioned, is it keeping the "out" directory from last build or meaning ccache or remote caching?
For incremental build (keeping the "out" directory from last build), previously we had met some kinds of compilation errors, so finally we decided to not use it.
We have already used CCACHE, and want to try RE + RC (remote caching) to reduce the building time further.
Do you have some benchmark data for your RE + RC service? Meanwhile I will try some 3rd-party RE services to see whether workable.
Many thanks for your support.