Masahiro Yamada's on January 15, 2019 7:01 pm: > Hi Nicholas, > > > On Tue, Jan 15, 2019 at 5:07 PM Nicholas Piggin <npiggin@xxxxxxxxx> wrote: >> >> Masahiro Yamada's on January 14, 2019 1:27 pm: >> > The symbol table in the final archive is unneeded because it is passed >> > to the linker after the --whole-archive option. Every object file in >> > the archive is included in the link anyway. >> > >> > Pass thin archives from subdirectories directly to the linker, and >> > remove the final archiving step. >> >> This seems like a good improvement. As far as I remember, it was slower >> to do the final link without the index built. Maybe I was testing it >> in a revision before moving those files into --whole-archive? If there >> is no slowdown, then I have no objection. > > > Thanks for the review. > > > I measured the performance of scripts/link-vmlinux.sh with 'perf stat'. > (20 times for each) > > > > Before this patch: > > Performance counter stats for 'make vmlinux' (20 runs): > > 5.266796537 seconds time elapsed > ( +- 0.12% ) > > > > After this patch: > > Performance counter stats for 'make vmlinux' (20 runs): > > 4.945576395 seconds time elapsed > > > > > So, the performance is slightly better. > > Maybe, does omitting the 'ar' save some time? Wow yeah that's a good speedup and simplification to boot. Thanks for checking it. > Anyway, this commit is good. Yes, it's a good improvement. Thanks, Nick
