Messages in this thread | | | From | Sedat Dilek <> | Date | Tue, 30 Mar 2021 14:31:30 +0200 | Subject | Re: [PATCH 0/2] x86: Remove ideal_nops[] |
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On Sat, Mar 27, 2021 at 9:02 PM Linus Torvalds <torvalds@linuxfoundation.org> wrote: > > On Sat, Mar 27, 2021 at 5:08 AM Sedat Dilek <sedat.dilek@gmail.com> wrote: > > > > debian-5.10.19 as host-kernel: > > 11655.755564957 seconds time elapsed > > > > dileks-5.12-rc3 plus x86-nops as host-kernel: > > 11941.439350080 seconds time elapsed > > That's 2.5% - a huge difference. Particularly since kernel build times > shouldn't even be that kernel-intensive. > > I think there's something else going on than the nops. Same config? > There are likely many other differences between 5.10.19 and 5.12-rc3. > > So can you check just plain 5.12-rc3 and then 5.12-rc3 plus x86-nops, > with otherwise identical configuration? >
Hi Linus,
I re-checked my linux-config and custom patchset.
I had "kbuild: add CONFIG_VMLINUX_MAP expert option" in my queue and build with CONFIG_VMLINUX_MAP=y. This option generated here an approx. 30MiB big vmlinux.map file. Cannot say how long this is taking in seconds but that can explain the the time-diff.
[ The above option is helpful to analyze a recent Linux-kernel build with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. Always, I was able to build but not boot on bare metal with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. With a LLVM toolchain, of course. ]
( In the meantime Debian has a 5.20.26 kernel released - so if you want I can re-test with Linux v5.12-rc5. )
Regards, - Sedat -
[1] https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/commit/?h=kbuild&id=babd8cd96d333cb83c9b8abf4f01ab1f161d6ec4
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