mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
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a6036a41bf
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 15f5db60a137 ("kbuild,arc: add
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC") without re-adding
ARCH_CFLAGS
Ever since
commit cfdbc2e16e65 ("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>
106 lines
2.7 KiB
Plaintext
106 lines
2.7 KiB
Plaintext
# CONFIG_LOCALVERSION_AUTO is not set
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CONFIG_DEFAULT_HOSTNAME="tb10x"
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CONFIG_SYSVIPC=y
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CONFIG_POSIX_MQUEUE=y
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# CONFIG_CROSS_MEMORY_ATTACH is not set
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CONFIG_HIGH_RES_TIMERS=y
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CONFIG_BSD_PROCESS_ACCT=y
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CONFIG_BSD_PROCESS_ACCT_V3=y
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CONFIG_IKCONFIG=y
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CONFIG_IKCONFIG_PROC=y
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CONFIG_LOG_BUF_SHIFT=16
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CONFIG_BLK_DEV_INITRD=y
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CONFIG_INITRAMFS_SOURCE="../tb10x-rootfs.cpio"
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CONFIG_INITRAMFS_ROOT_UID=2100
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CONFIG_INITRAMFS_ROOT_GID=501
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# CONFIG_RD_GZIP is not set
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CONFIG_KALLSYMS_ALL=y
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# CONFIG_AIO is not set
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CONFIG_EMBEDDED=y
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# CONFIG_COMPAT_BRK is not set
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CONFIG_ISA_ARCOMPACT=y
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CONFIG_SLAB=y
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CONFIG_MODULES=y
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CONFIG_MODULE_FORCE_LOAD=y
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CONFIG_MODULE_UNLOAD=y
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# CONFIG_BLOCK is not set
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CONFIG_ARC_PLAT_TB10X=y
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CONFIG_ARC_CACHE_LINE_SHIFT=5
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CONFIG_HZ=250
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CONFIG_ARC_BUILTIN_DTB_NAME="abilis_tb100_dvk"
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CONFIG_PREEMPT_VOLUNTARY=y
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# CONFIG_COMPACTION is not set
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CONFIG_NET=y
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CONFIG_PACKET=y
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CONFIG_UNIX=y
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CONFIG_INET=y
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CONFIG_IP_MULTICAST=y
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# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
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# CONFIG_INET_XFRM_MODE_TUNNEL is not set
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# CONFIG_INET_XFRM_MODE_BEET is not set
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# CONFIG_INET_DIAG is not set
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# CONFIG_IPV6 is not set
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# CONFIG_WIRELESS is not set
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CONFIG_DEVTMPFS=y
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CONFIG_NETDEVICES=y
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# CONFIG_NET_CADENCE is not set
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# CONFIG_NET_VENDOR_BROADCOM is not set
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# CONFIG_NET_VENDOR_INTEL is not set
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# CONFIG_NET_VENDOR_MARVELL is not set
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# CONFIG_NET_VENDOR_MICREL is not set
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# CONFIG_NET_VENDOR_NATSEMI is not set
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# CONFIG_NET_VENDOR_SEEQ is not set
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CONFIG_STMMAC_ETH=y
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# CONFIG_NET_VENDOR_WIZNET is not set
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# CONFIG_WLAN is not set
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# CONFIG_INPUT is not set
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# CONFIG_SERIO is not set
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# CONFIG_VT is not set
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# CONFIG_LEGACY_PTYS is not set
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CONFIG_SERIAL_8250=y
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CONFIG_SERIAL_8250_CONSOLE=y
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CONFIG_SERIAL_8250_NR_UARTS=1
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CONFIG_SERIAL_8250_RUNTIME_UARTS=1
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CONFIG_SERIAL_8250_DW=y
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# CONFIG_HW_RANDOM is not set
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CONFIG_I2C=y
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# CONFIG_I2C_COMPAT is not set
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CONFIG_I2C_DESIGNWARE_PLATFORM=y
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CONFIG_GPIO_SYSFS=y
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# CONFIG_HWMON is not set
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# CONFIG_USB_SUPPORT is not set
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CONFIG_NEW_LEDS=y
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CONFIG_LEDS_CLASS=y
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CONFIG_LEDS_GPIO=y
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CONFIG_LEDS_TRIGGERS=y
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CONFIG_LEDS_TRIGGER_TIMER=y
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CONFIG_LEDS_TRIGGER_ONESHOT=y
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CONFIG_LEDS_TRIGGER_HEARTBEAT=y
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CONFIG_LEDS_TRIGGER_CPU=y
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CONFIG_LEDS_TRIGGER_GPIO=y
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CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
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CONFIG_LEDS_TRIGGER_TRANSIENT=y
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CONFIG_DMADEVICES=y
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CONFIG_DW_DMAC=y
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CONFIG_ASYNC_TX_DMA=y
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# CONFIG_IOMMU_SUPPORT is not set
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# CONFIG_DNOTIFY is not set
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CONFIG_PROC_KCORE=y
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CONFIG_TMPFS=y
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CONFIG_CONFIGFS_FS=y
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# CONFIG_MISC_FILESYSTEMS is not set
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# CONFIG_NETWORK_FILESYSTEMS is not set
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CONFIG_DEBUG_INFO=y
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CONFIG_STRIP_ASM_SYMS=y
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CONFIG_DEBUG_FS=y
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CONFIG_HEADERS_INSTALL=y
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CONFIG_HEADERS_CHECK=y
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CONFIG_DEBUG_SECTION_MISMATCH=y
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CONFIG_MAGIC_SYSRQ=y
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CONFIG_DEBUG_MEMORY_INIT=y
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CONFIG_DEBUG_STACKOVERFLOW=y
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CONFIG_DETECT_HUNG_TASK=y
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CONFIG_SCHEDSTATS=y
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CONFIG_TIMER_STATS=y
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# CONFIG_CRYPTO_HW is not set
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