On Sat, May 25, 2019 at 09:19:39AM +0700, Robert Elz wrote: > | My observation was general that this syscall is frequently called by > | many programs. Optimization of it can potentially change responsiveness > | of the whole system. > > Yes, gettimeofday() is very common - but we need to investigate how > to speed it up, not just presume that a mapped page is the right answer. > > Using a mapped page would mean processes would only see the time as it was > last updated in the kernel -
That obviously sucks :-) The general mapped page scheme is that the processor has some kind of usermode-accessible tick counter or timer and the mapped page contains the offset and/or scale needed to convert that to a useful time. On old processors without such a widget, it basically doesn't work. > I am sure there are, but I very much doubt that build.sh is really something > itself that ought to be a target of investigation. All it is is a wrapper > around make. All the real work is done in make, and all that it calls. > Speeding up build.sh itself is very unlikely to change anything, unless we > can find entire runs of make that we can optimise away. make is very slow :-| -- David A. Holland dholl...@netbsd.org
