On Fri, Jun 17, 2022 at 12:35 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > On Fri, Jun 17, 2022 at 12:53 AM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > On Thu, Jun 16, 2022 at 4:09 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > > > On Thu, Jun 16, 2022 at 12:45 PM Jiri Slaby <jslaby@xxxxxxx> wrote: > > > > > > > > Until the link-vmlinux.sh split (cf. the commit below), the linker was > > > > run with jobserver set in MAKEFLAGS. After the split, the command in > > > > Makefile.vmlinux_o is not prefixed by "+" anymore, so this information > > > > is lost. > > > > > > > > Restore it as linkers working in parallel (esp. the LTO ones) make a use > > > > of it. > > > > > > > > Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx> > > > > Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> > > > > Cc: Michal Marek <michal.lkml@xxxxxxxxxxx> > > > > Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > > > > Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o) > > > > Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> > > > > > > Nice catch. > > > ( I have seen some slowdown in my build-time. Will test and report. ) > > > > > > Reviewed-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> > > > > > > > No measurable difference in build-time. > > > > Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> # LLVM-14 (x86-64) > > > > [ CC Nathan and Sami ] > > I re-checked as my build-time takes approx. 15mins more than usual > with Linux v5.17. > > [ Perf - seconds time elapsed ] > v5.17: approx. 12500 > v5.19: approx. 13500 > > +1.000 secs = +16,67mins > > I am still investigating. > > I use LLVM v14.0.4 and CONFIG_LTO_CLANG_THIN=y. > > When I check for... > > $ egrep 'Makefile.vmlinux_o|jobserver-exec|link-vmlinux.sh' > build-log_5.19.0-rc2-2-amd64-clang14-lto.txt > 61414: sh scripts/link-vmlinux.sh "ld.lld" "-m elf_x86_64 > --thinlto-cache-dir=.thinlto-cache -mllvm -import-instr-limit=5" > "--emit-relocs --discard-none -z max-page-size=0x200000 > --build-id=sha1 -X --orphan-handling=warn"; true > 61426:+ make -f ./scripts/Makefile.vmlinux_o > 61427: python3 ./scripts/jobserver-exec perl > scripts/generate_initcall_order.pl arch/x86/kernel/head_64.o > arch/x86/kernel/head64.o arch/x86/kernel/ebda.o > arch/x86/kernel/platform-quirks.o init/built-in.a usr/built-in.a > arch/x86/built-in.a kernel/built-in.a certs/built-in.a mm/built-in.a > fs/built-in.a ipc/built-in.a security/built-i > n.a crypto/built-in.a block/built-in.a lib/built-in.a > arch/x86/lib/built-in.a lib/lib.a arch/x86/lib/lib.a > drivers/built-in.a sound/built-in.a net/built-in.a virt/buil > t-in.a arch/x86/pci/built-in.a arch/x86/power/built-in.a > arch/x86/video/built-in.a > .tmp_initcalls.lds > 61693:+ echo vmlinux: scripts/link-vmlinux.sh > > Plus vmlinux.o > > 61428: ld.lld -m elf_x86_64 --thinlto-cache-dir=.thinlto-cache -mllvm > -import-instr-limit=5 -r -o vmlinux.o -T .tmp_initcalls.lds > --whole-archive arch/x86/kernel/head_64.o arch/x86/kernel/head64.o > arch/x86/kernel/ebda.o arch/x86/kernel/platform-quirks.o > init/built-in.a usr/built-in.a arch/x86/built-in.a kernel/built-in.a > certs/built-in.a mm/built-in.a fs/built-in.a ipc/built-in.a > security/built-in.a crypto/built-in.a block/built-in.a lib/built-in.a > arch/x86/lib/built-in.a lib/lib.a arch/x86/lib/lib.a > drivers/built-in.a sound/built-in.a net/built-in.a virt/built-in.a > arch/x86/pci/built-in.a arch/x86/power/built-in.a > arch/x86/video/built-in.a --no-whole-archive --start-group > --end-group ; ./tools/objtool/objtool --hacks=jump_label > --hacks=noinstr --mcount --orc --retpoline --static-call > --uaccess --link -- > link vmlinux.o > > Pooh, truncated via Gmail? Attached as a file. > > Checking via ps... > > $ ps -ef | grep l[l]d > lld-jobserver.txt > > ...and top util shows me only one lld link-job is running (file attached). > > Unsure, if in my setup lld linker benefits from jobserver feature or not. > > Am I missing something? > > My kernel-config is attached. > Found this... $ ld.lld-14 --help --thinlto-jobs=<value> Number of ThinLTO jobs. Default to --threads= -Sedat-
