I am profiling a program where the vast majority (86%) of time is spent in two runtime functions: kevent and selectgo. I understand the select, but I don't know what kevent is (so I don't know where to start optimizing):
Showing top 10 nodes out of 33
flat flat% sum% cum cum%
114.63s 65.79% 65.79% 114.63s 65.79% runtime.kevent /usr/local/Cellar/go/1.9.2/libexec/src/runtime/sys_darwin_amd64.s
19.26s 11.05% 76.85% 35.90s 20.60% runtime.selectgo /usr/local/Cellar/go/1.9.2/libexec/src/runtime/select.go