Hi Peter and Petr, Thanks for your suggestions, will try to find a cleaner and less hacky way, and it may take some time as dealing with all kinds of TSC is tricky :)
- Feng On Thu, May 31, 2018 at 05:52:10PM +0200, Peter Zijlstra wrote: > On Thu, May 31, 2018 at 03:55:42PM +0200, Petr Mladek wrote: > > I wonder if we could get some cleaner integration into the timer and > > printk code. > > Yes, these patches are particularly horrific.. > > There were some earlier patches by Pavel Tatashin, which attempted do > get things running earlier. > > http://lkml.kernel.org/r/20180209211143.16215-1-pasha.tatas...@oracle.com > > I'm not entirely happy with that, but I never did get around to > reviewing that last version :-( In particuarly, now that you made me > look, I dislike his patch 6 almost as much as these patches. > > The idea was to get regular sched_clock() running earlier, not to botch > some early_sched_clock() into it. > > Basically run calibrate_tsc() earlier (like _waaay_ earlier, it doesn't > rely on anything other than CPUID) and if you have a recent part (with > exception of SKX) you'll get a usable tsc rate (and TSC_RELIABLE) and > things will work. > > If you have a dodgy part (sorry SKX), you'll just have to live with > sched_clock starting late(r). > > Do not cobble things on the side, try and get the normal things running > earlier.
