Hello, On Wed, Nov 22, 2017 at 12:52 AM, Raffaele Belardi <raffaele.bela...@st.com> wrote: > Hi, > > rebuilding system and world with gcc-7.2.0 on a 6-core AMD CPU I have the > impression that > most of the ebuilds limit parallel builds to 1, 2 or 3 threads. I'm aware it > is only an > impression, I did not spend the night monitoring the process, but > nevertheless every time > I checked the load was very low. >
Assuming all of your compilation is on a RAM disk, there are two main bottlenecks that are easy to spot: network access (downloading new packages) and dependency chokepoints (packages must be compiled in a chain). Other potential chokepoints like disk access are negligible in my experience, though for one merge I did have two or three ebuilds fighting for disk IO "lock up" a system. If all dependencies have been satisfied on your system I invite you to merge a bunch of packages at once (@world?), you should notice greater parallelism. > Does anyone have real-world statistics of CPU usage based on gentoo world > build? > I've considered ways to gather these statistics off and on over the years, but it is easy to start sinking a lot of time into it. It is possible the data you want exists, but I have not found any extant solution involving portage that provides that detail of logging.* Cheers, R0b0t1 * Someone will prove me wrong in 3... 2... 1...