With the help of the tool
qlop from the collection of utilities called q applets you can check how long it took to install a package in Gentoo. qlop reads from your log
$EMERGE_LOG_DIR/emerge.log and extracts relevant information.
# qlop -Ht qtwebengine [...] 2020-02-19T16:58:02 >>> dev-qt/qtwebengine: 2 hours, 14 minutes, 17 seconds 2020-03-31T01:27:45 >>> dev-qt/qtwebengine: 2 hours, 12 minutes, 43 seconds 2020-05-28T10:24:16 >>> dev-qt/qtwebengine: 2 hours, 22 minutes, 6 seconds
-t lists all installations and the flag
-H prints the time in a human readable format.
If you would like to see the average time it has taken to install a certain package you can do so with the flag
# qlop -Ha qtwebengine dev-qt/qtwebengine: 2 hours, 6 minutes, 24 seconds average for 19 merges dev-qt/qtwebengine: 2 seconds average for 1 unmerge
Don’t forget to check out all the available features with the flag
The tool is available in the package
# emerge --ask app-portage/portage-utils