On Thu, Nov 07, 2019 at 10:32:01PM +0800, shile.zhang@xxxxxxxxxxxxxxxxx wrote: > From: Shile Zhang <shile.zhang@xxxxxxxxxxxxxxxxx> > > Hi, > > I found the unwind_init taken long time (more than 90ms) in kernel > booting, mainly spent on sorting the two ORC unwind tables, orc_unwind > and orc_unwind_ip. > > I also noticed that this issued has reported and discussed last year: > https://lkml.org/lkml/2018/10/8/342 > But seems no final solution until now, I tried to sort the ORC tables at > build time, followed the helpful hints from Josh and Ingo in that thread. > And mainly referred the implementation of 'sortextable' tool: > https://lore.kernel.org/linux-mips/1334872799-14589-1-git-send-email-ddaney.cavm@xxxxxxxxx/ > > What I did: > > - Add a Kconfig to control build-time sorting or runtime sorting; > - Referred 'sortextable', create a similar helper tool 'sortorctable', > help to sort the ORC unwind tables at vmlinux link process. What is the build-time cost for doing this? The link phase is already a fairly big bottleneck for building a kernel. Can sort{ex,orc}table() be ran concurrently? Do they want to be the same (threaded) tool?
