Nick Desaulniers a6036a41bf kbuild: drop support for CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 ... The difference in most compilers between `-O3` and `-O2` is mostly down to whether loops with statically determinable trip counts are fully unrolled vs unrolled to a multiple of SIMD width. This patch is effectively a revert of commit 15f5db60a1 ("kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC") without re-adding ARCH_CFLAGS Ever since commit cfdbc2e16e ("ARC: Build system: Makefiles, Kconfig, Linker script") ARC has been built with -O3, though the reason for doing so was not specified in inline comments or the commit message. This commit does not re-add -O3 to arch/arc/Makefile. Folks looking to experiment with `-O3` (or any compiler flag for that matter) may pass them along to the command line invocation of make: $ make KCFLAGS=-O3 Code that looks to re-add an explicit Kconfig option for `-O3` should provide: 1. A rigorous and reproducible performance profile of a reasonable userspace workload that demonstrates a hot loop in the kernel that would benefit from `-O3` over `-O2`. 2. Disassembly of said loop body before and after. 3. Provides stats on terms of increase in file size. Link: https://lore.kernel.org/linux-kbuild/CA+55aFz2sNBbZyg-_i8_Ldr2e8o9dfvdSfHHuRzVtP2VMAUWPg@mail.gmail.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>		2022-07-27 21:17:59 +09:00
..
boot	ARC: dts: align SPI NOR node name with dtschema	2022-04-18 12:22:31 -07:00
configs	kbuild: drop support for CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3	2022-07-27 21:17:59 +09:00
include	ARC: bpf: define uapi for BPF_PROG_TYPE_PERF_EVENT program type	2022-04-26 09:35:28 -07:00
kernel	This set of changes updates init and user mode helper tasks to be	2022-06-03 16:03:05 -07:00
lib	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
mm	ARC: fix typos in comments	2022-04-18 12:20:23 -07:00
plat-axs10x	arc: Replace lkml.org links with lore	2021-12-28 19:48:49 -08:00
plat-hsdk	arc: Replace lkml.org links with lore	2021-12-28 19:48:49 -08:00
plat-sim	ARC: merge HAPS-HS with nSIM-HS configs	2019-10-28 12:12:31 -07:00
plat-tb10x	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333	2019-06-05 17:37:06 +02:00
Kbuild	kbuild: use more subdir- for visiting subdirectories while cleaning	2021-10-24 13:49:46 +09:00
Kconfig	ARC: implement syscall tracepoints	2022-04-25 13:09:47 -07:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Makefile	kbuild: do not quote string values in include/config/auto.conf	2022-01-08 18:03:57 +09:00