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linux-yocto/arch/arc/configs/haps_hs_defconfig
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

1.6 KiB
Raw Blame History

CONFIG_SWAP is not set

CONFIG_SYSVIPC=y CONFIG_POSIX_MQUEUE=y

CONFIG_CROSS_MEMORY_ATTACH is not set

CONFIG_NO_HZ_IDLE=y CONFIG_HIGH_RES_TIMERS=y CONFIG_PREEMPT=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_NAMESPACES=y

CONFIG_UTS_NS is not set

CONFIG_PID_NS is not set

CONFIG_BLK_DEV_INITRD=y CONFIG_EXPERT=y CONFIG_PERF_EVENTS=y

CONFIG_COMPAT_BRK is not set

CONFIG_SLAB=y CONFIG_ARC_BUILTIN_DTB_NAME="haps_hs" CONFIG_MODULES=y

CONFIG_BLK_DEV_BSG is not set

CONFIG_COMPACTION is not set

CONFIG_NET=y CONFIG_PACKET=y CONFIG_PACKET_DIAG=y CONFIG_UNIX=y CONFIG_UNIX_DIAG=y CONFIG_NET_KEY=y CONFIG_INET=y

CONFIG_IPV6 is not set

CONFIG_WIRELESS is not set

CONFIG_DEVTMPFS=y CONFIG_DEVTMPFS_MOUNT=y

CONFIG_STANDALONE is not set

CONFIG_PREVENT_FIRMWARE_BUILD is not set

CONFIG_VIRTIO_BLK=y CONFIG_NETDEVICES=y CONFIG_VIRTIO_NET=y

CONFIG_ETHERNET is not set

CONFIG_WLAN is not set

CONFIG_INPUT_EVDEV=y

CONFIG_INPUT_KEYBOARD is not set

CONFIG_INPUT_MOUSE is not set

CONFIG_SERIO is not set

CONFIG_LEGACY_PTYS is not set

CONFIG_SERIAL_8250=y CONFIG_SERIAL_8250_CONSOLE=y CONFIG_SERIAL_8250_NR_UARTS=1 CONFIG_SERIAL_8250_RUNTIME_UARTS=1 CONFIG_SERIAL_8250_DW=y CONFIG_SERIAL_OF_PLATFORM=y

CONFIG_HW_RANDOM is not set

CONFIG_HWMON is not set

CONFIG_HID is not set

CONFIG_USB_SUPPORT is not set

CONFIG_VIRTIO_MMIO=y

CONFIG_IOMMU_SUPPORT is not set

CONFIG_EXT2_FS=y CONFIG_EXT2_FS_XATTR=y CONFIG_TMPFS=y

CONFIG_MISC_FILESYSTEMS is not set

CONFIG_NFS_FS=y

CONFIG_ENABLE_MUST_CHECK is not set

CONFIG_DEBUG_MEMORY_INIT=y

CONFIG_DEBUG_PREEMPT is not set