| Message ID | 20190820170941.26193-2-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/3] init/Kconfig: rework help of CONFIG_CC_OPTIMIZE_FOR_SIZE | expand |
Hi Vineet, On Wed, Aug 21, 2019 at 2:10 AM Masahiro Yamada <yamada.masahiro@socionext.com> wrote: > > arch/arc/Makefile overrides -O2 with -O3. This is the only user of > ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS. > My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC > Makefile. > > Currently, ARC has no way to enable -Wmaybe-uninitialized because both > -O3 and -Os disable it. Enabling it will be useful for compile-testing. > This commit allows allmodconfig (, which defaults to -O2) to enable it. > > Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files > in arch/arc/configs/ in order to keep the current config settings. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- If it is OK to apply this to my kbuild tree, can I get your ACK? If you see any problem, please let me know. Thanks. > > Makefile | 10 ++++++---- > arch/arc/Makefile | 8 -------- > arch/arc/configs/axs101_defconfig | 1 + > arch/arc/configs/axs103_defconfig | 1 + > arch/arc/configs/axs103_smp_defconfig | 1 + > arch/arc/configs/haps_hs_defconfig | 1 + > arch/arc/configs/haps_hs_smp_defconfig | 1 + > arch/arc/configs/hsdk_defconfig | 1 + > arch/arc/configs/nps_defconfig | 1 + > arch/arc/configs/nsim_700_defconfig | 1 + > arch/arc/configs/nsim_hs_defconfig | 1 + > arch/arc/configs/nsim_hs_smp_defconfig | 1 + > arch/arc/configs/nsimosci_defconfig | 1 + > arch/arc/configs/nsimosci_hs_defconfig | 1 + > arch/arc/configs/nsimosci_hs_smp_defconfig | 1 + > arch/arc/configs/tb10x_defconfig | 1 + > arch/arc/configs/vdk_hs38_defconfig | 1 + > arch/arc/configs/vdk_hs38_smp_defconfig | 1 + > init/Kconfig | 12 ++++++++++-- > 19 files changed, 32 insertions(+), 14 deletions(-) > > diff --git a/Makefile b/Makefile > index bc55f366677d..891e47da503f 100644 > --- a/Makefile > +++ b/Makefile > @@ -716,10 +716,12 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) > KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) > KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > > -ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > -KBUILD_CFLAGS += -Os > -else > -KBUILD_CFLAGS += -O2 > +ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE > +KBUILD_CFLAGS += -O2 > +else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 > +KBUILD_CFLAGS += -O3 > +else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > +KBUILD_CFLAGS += -Os > endif > > ifdef CONFIG_CC_DISABLE_WARN_MAYBE_UNINITIALIZED > diff --git a/arch/arc/Makefile b/arch/arc/Makefile > index ee6d1184c2b1..f1c44cccf8d6 100644 > --- a/arch/arc/Makefile > +++ b/arch/arc/Makefile > @@ -48,14 +48,6 @@ endif > cfi := $(call as-instr,.cfi_startproc\n.cfi_endproc,-DARC_DW2_UNWIND_AS_CFI) > cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi) > > -ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE > -# Generic build system uses -O2, we want -O3 > -# Note: No need to add to cflags-y as that happens anyways > -# > -# Disable the false maybe-uninitialized warings gcc spits out at -O3 > -ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,) > -endif > - > # small data is default for elf32 tool-chain. If not usable, disable it > # This also allows repurposing GP as scratch reg to gcc reg allocator > disable_small_data := y > diff --git a/arch/arc/configs/axs101_defconfig b/arch/arc/configs/axs101_defconfig > index e31a8ebc3ecc..0016149f9583 100644 > --- a/arch/arc/configs/axs101_defconfig > +++ b/arch/arc/configs/axs101_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/axs103_defconfig b/arch/arc/configs/axs103_defconfig > index e0e8567f0d75..5b031582a1cf 100644 > --- a/arch/arc/configs/axs103_defconfig > +++ b/arch/arc/configs/axs103_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/axs103_smp_defconfig b/arch/arc/configs/axs103_smp_defconfig > index fcbc952bc75b..d4eec39e0112 100644 > --- a/arch/arc/configs/axs103_smp_defconfig > +++ b/arch/arc/configs/axs103_smp_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/haps_hs_defconfig b/arch/arc/configs/haps_hs_defconfig > index 436f2135bdc1..47ff8a97e42d 100644 > --- a/arch/arc/configs/haps_hs_defconfig > +++ b/arch/arc/configs/haps_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EXPERT=y > CONFIG_PERF_EVENTS=y > # CONFIG_COMPAT_BRK is not set > diff --git a/arch/arc/configs/haps_hs_smp_defconfig b/arch/arc/configs/haps_hs_smp_defconfig > index 33a787c375e2..9685fd5f57a4 100644 > --- a/arch/arc/configs/haps_hs_smp_defconfig > +++ b/arch/arc/configs/haps_hs_smp_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/hsdk_defconfig b/arch/arc/configs/hsdk_defconfig > index 403125d9c9a3..9b9a74444ce2 100644 > --- a/arch/arc/configs/hsdk_defconfig > +++ b/arch/arc/configs/hsdk_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > CONFIG_BLK_DEV_RAM=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/nps_defconfig b/arch/arc/configs/nps_defconfig > index f0a077c00efa..5978d4d7d5b0 100644 > --- a/arch/arc/configs/nps_defconfig > +++ b/arch/arc/configs/nps_defconfig > @@ -6,6 +6,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_SYSCTL_SYSCALL=y > # CONFIG_EPOLL is not set > # CONFIG_SIGNALFD is not set > diff --git a/arch/arc/configs/nsim_700_defconfig b/arch/arc/configs/nsim_700_defconfig > index de398c7b10b3..2b9b11474640 100644 > --- a/arch/arc/configs/nsim_700_defconfig > +++ b/arch/arc/configs/nsim_700_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsim_hs_defconfig b/arch/arc/configs/nsim_hs_defconfig > index 2dbd34a9ff07..bab3dd255841 100644 > --- a/arch/arc/configs/nsim_hs_defconfig > +++ b/arch/arc/configs/nsim_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsim_hs_smp_defconfig b/arch/arc/configs/nsim_hs_smp_defconfig > index c7135f1e2583..90d2d50fb8dc 100644 > --- a/arch/arc/configs/nsim_hs_smp_defconfig > +++ b/arch/arc/configs/nsim_hs_smp_defconfig > @@ -8,6 +8,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_defconfig b/arch/arc/configs/nsimosci_defconfig > index 385a71d3c478..5dd470b6609e 100644 > --- a/arch/arc/configs/nsimosci_defconfig > +++ b/arch/arc/configs/nsimosci_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_hs_defconfig b/arch/arc/configs/nsimosci_hs_defconfig > index 248a2c3bdc12..3532e86f7bff 100644 > --- a/arch/arc/configs/nsimosci_hs_defconfig > +++ b/arch/arc/configs/nsimosci_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_hs_smp_defconfig b/arch/arc/configs/nsimosci_hs_smp_defconfig > index 1a4bc7b660fb..d90448bee064 100644 > --- a/arch/arc/configs/nsimosci_hs_smp_defconfig > +++ b/arch/arc/configs/nsimosci_hs_smp_defconfig > @@ -8,6 +8,7 @@ CONFIG_IKCONFIG_PROC=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_PERF_EVENTS=y > # CONFIG_COMPAT_BRK is not set > CONFIG_KPROBES=y > diff --git a/arch/arc/configs/tb10x_defconfig b/arch/arc/configs/tb10x_defconfig > index dc739bd093e3..3a138f8c7299 100644 > --- a/arch/arc/configs/tb10x_defconfig > +++ b/arch/arc/configs/tb10x_defconfig > @@ -14,6 +14,7 @@ CONFIG_INITRAMFS_SOURCE="../tb10x-rootfs.cpio" > CONFIG_INITRAMFS_ROOT_UID=2100 > CONFIG_INITRAMFS_ROOT_GID=501 > # CONFIG_RD_GZIP is not set > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_SYSCTL_SYSCALL=y > CONFIG_KALLSYMS_ALL=y > # CONFIG_AIO is not set > diff --git a/arch/arc/configs/vdk_hs38_defconfig b/arch/arc/configs/vdk_hs38_defconfig > index 0c3b21416819..d7c858df520c 100644 > --- a/arch/arc/configs/vdk_hs38_defconfig > +++ b/arch/arc/configs/vdk_hs38_defconfig > @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/vdk_hs38_smp_defconfig b/arch/arc/configs/vdk_hs38_smp_defconfig > index f9ad9d3ee702..015c1d43889e 100644 > --- a/arch/arc/configs/vdk_hs38_smp_defconfig > +++ b/arch/arc/configs/vdk_hs38_smp_defconfig > @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/init/Kconfig b/init/Kconfig > index 149efd82447f..92118505dd33 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1209,14 +1209,22 @@ choice > default CC_OPTIMIZE_FOR_PERFORMANCE > > config CC_OPTIMIZE_FOR_PERFORMANCE > - bool "Optimize for performance" > + bool "Optimize for performance (-O2)" > help > This is the default optimization level for the kernel, building > with the "-O2" compiler flag for best performance and most > helpful compile-time warnings. > > +config CC_OPTIMIZE_FOR_PERFORMANCE_O3 > + bool "Optimize more for performance (-O3)" > + depends on ARC > + imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives > + help > + Choosing this option will pass "-O3" to your compiler to optimize > + the kernel yet more for performance. > + > config CC_OPTIMIZE_FOR_SIZE > - bool "Optimize for size" > + bool "Optimize for size (-Os)" > imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives > help > Choosing this option will pass "-Os" to your compiler resulting > -- > 2.17.1 >
On 8/20/19 10:09 AM, Masahiro Yamada wrote: > arch/arc/Makefile overrides -O2 with -O3. This is the only user of > ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS. > My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC > Makefile. Why, it seems like a good generic facility for arches to over-ride stuff (specially adding any toggles at the end of cmdline). And even if there are no current users, it would be good to have. I understand we don't keep code for future, but strictly this is meta-code ;-) > Currently, ARC has no way to enable -Wmaybe-uninitialized because both > -O3 and -Os disable it. Enabling it will be useful for compile-testing. > This commit allows allmodconfig (, which defaults to -O2) to enable it. But this is a separate issue and was done on purpose because of unbearable build spew at the time. As an experiment I enabled it in current kernel and at -O3 we still get the dreaded spew in net/sunrpc/xdr.c and some more in net/ipv4. The spew doesn't happen at -O2 and seems not ARC specific as I can see this with ARM -O3 build with gcc 7.3 (buildroot 2018.08) | $ make ARCH=arm CROSS_COMPILE=arm-linux- net | ...... | ...... | ../net/sunrpc/xdr.c: In function ‘xdr_encode_word’: | ../net/sunrpc/xdr.c:1199:2: warning: ‘subbuf.tail[0].iov_base’ may be used | uninitialized in this function [-Wmaybe-uninitialized] | memcpy(subbuf->tail[0].iov_base, obj, this_len); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ../net/sunrpc/xdr.c:1205:17: note: ‘subbuf.tail[0].iov_base’ was declared here | struct xdr_buf subbuf; I understand the value of this toggle, but the spew is too much and at times obfuscated likely other real issues. > Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files > in arch/arc/configs/ in order to keep the current config settings. My first reaction to adding this to all defconfigs was that this was inelegant : for lack of better word :-) But indeed it seems better this way as we can now experiment with -O2 vs. -O3 from config, rather than hardwiring to -O3. So if you could please split out the Wmaybe-uninitialized change Acked-by: Vineet Gupta <vgupta@synopsys.com> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > Makefile | 10 ++++++---- > arch/arc/Makefile | 8 -------- > arch/arc/configs/axs101_defconfig | 1 + > arch/arc/configs/axs103_defconfig | 1 + > arch/arc/configs/axs103_smp_defconfig | 1 + > arch/arc/configs/haps_hs_defconfig | 1 + > arch/arc/configs/haps_hs_smp_defconfig | 1 + > arch/arc/configs/hsdk_defconfig | 1 + > arch/arc/configs/nps_defconfig | 1 + > arch/arc/configs/nsim_700_defconfig | 1 + > arch/arc/configs/nsim_hs_defconfig | 1 + > arch/arc/configs/nsim_hs_smp_defconfig | 1 + > arch/arc/configs/nsimosci_defconfig | 1 + > arch/arc/configs/nsimosci_hs_defconfig | 1 + > arch/arc/configs/nsimosci_hs_smp_defconfig | 1 + > arch/arc/configs/tb10x_defconfig | 1 + > arch/arc/configs/vdk_hs38_defconfig | 1 + > arch/arc/configs/vdk_hs38_smp_defconfig | 1 + > init/Kconfig | 12 ++++++++++-- > 19 files changed, 32 insertions(+), 14 deletions(-) > > diff --git a/Makefile b/Makefile > index bc55f366677d..891e47da503f 100644 > --- a/Makefile > +++ b/Makefile > @@ -716,10 +716,12 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) > KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) > KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > > -ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > -KBUILD_CFLAGS += -Os > -else > -KBUILD_CFLAGS += -O2 > +ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE > +KBUILD_CFLAGS += -O2 > +else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 > +KBUILD_CFLAGS += -O3 > +else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > +KBUILD_CFLAGS += -Os > endif > > ifdef CONFIG_CC_DISABLE_WARN_MAYBE_UNINITIALIZED > diff --git a/arch/arc/Makefile b/arch/arc/Makefile > index ee6d1184c2b1..f1c44cccf8d6 100644 > --- a/arch/arc/Makefile > +++ b/arch/arc/Makefile > @@ -48,14 +48,6 @@ endif > cfi := $(call as-instr,.cfi_startproc\n.cfi_endproc,-DARC_DW2_UNWIND_AS_CFI) > cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi) > > -ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE > -# Generic build system uses -O2, we want -O3 > -# Note: No need to add to cflags-y as that happens anyways > -# > -# Disable the false maybe-uninitialized warings gcc spits out at -O3 > -ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,) > -endif > - > # small data is default for elf32 tool-chain. If not usable, disable it > # This also allows repurposing GP as scratch reg to gcc reg allocator > disable_small_data := y > diff --git a/arch/arc/configs/axs101_defconfig b/arch/arc/configs/axs101_defconfig > index e31a8ebc3ecc..0016149f9583 100644 > --- a/arch/arc/configs/axs101_defconfig > +++ b/arch/arc/configs/axs101_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/axs103_defconfig b/arch/arc/configs/axs103_defconfig > index e0e8567f0d75..5b031582a1cf 100644 > --- a/arch/arc/configs/axs103_defconfig > +++ b/arch/arc/configs/axs103_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/axs103_smp_defconfig b/arch/arc/configs/axs103_smp_defconfig > index fcbc952bc75b..d4eec39e0112 100644 > --- a/arch/arc/configs/axs103_smp_defconfig > +++ b/arch/arc/configs/axs103_smp_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/haps_hs_defconfig b/arch/arc/configs/haps_hs_defconfig > index 436f2135bdc1..47ff8a97e42d 100644 > --- a/arch/arc/configs/haps_hs_defconfig > +++ b/arch/arc/configs/haps_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EXPERT=y > CONFIG_PERF_EVENTS=y > # CONFIG_COMPAT_BRK is not set > diff --git a/arch/arc/configs/haps_hs_smp_defconfig b/arch/arc/configs/haps_hs_smp_defconfig > index 33a787c375e2..9685fd5f57a4 100644 > --- a/arch/arc/configs/haps_hs_smp_defconfig > +++ b/arch/arc/configs/haps_hs_smp_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/hsdk_defconfig b/arch/arc/configs/hsdk_defconfig > index 403125d9c9a3..9b9a74444ce2 100644 > --- a/arch/arc/configs/hsdk_defconfig > +++ b/arch/arc/configs/hsdk_defconfig > @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > CONFIG_BLK_DEV_RAM=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/nps_defconfig b/arch/arc/configs/nps_defconfig > index f0a077c00efa..5978d4d7d5b0 100644 > --- a/arch/arc/configs/nps_defconfig > +++ b/arch/arc/configs/nps_defconfig > @@ -6,6 +6,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_SYSCTL_SYSCALL=y > # CONFIG_EPOLL is not set > # CONFIG_SIGNALFD is not set > diff --git a/arch/arc/configs/nsim_700_defconfig b/arch/arc/configs/nsim_700_defconfig > index de398c7b10b3..2b9b11474640 100644 > --- a/arch/arc/configs/nsim_700_defconfig > +++ b/arch/arc/configs/nsim_700_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsim_hs_defconfig b/arch/arc/configs/nsim_hs_defconfig > index 2dbd34a9ff07..bab3dd255841 100644 > --- a/arch/arc/configs/nsim_hs_defconfig > +++ b/arch/arc/configs/nsim_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsim_hs_smp_defconfig b/arch/arc/configs/nsim_hs_smp_defconfig > index c7135f1e2583..90d2d50fb8dc 100644 > --- a/arch/arc/configs/nsim_hs_smp_defconfig > +++ b/arch/arc/configs/nsim_hs_smp_defconfig > @@ -8,6 +8,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_defconfig b/arch/arc/configs/nsimosci_defconfig > index 385a71d3c478..5dd470b6609e 100644 > --- a/arch/arc/configs/nsimosci_defconfig > +++ b/arch/arc/configs/nsimosci_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_hs_defconfig b/arch/arc/configs/nsimosci_hs_defconfig > index 248a2c3bdc12..3532e86f7bff 100644 > --- a/arch/arc/configs/nsimosci_hs_defconfig > +++ b/arch/arc/configs/nsimosci_hs_defconfig > @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_KALLSYMS_ALL=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > diff --git a/arch/arc/configs/nsimosci_hs_smp_defconfig b/arch/arc/configs/nsimosci_hs_smp_defconfig > index 1a4bc7b660fb..d90448bee064 100644 > --- a/arch/arc/configs/nsimosci_hs_smp_defconfig > +++ b/arch/arc/configs/nsimosci_hs_smp_defconfig > @@ -8,6 +8,7 @@ CONFIG_IKCONFIG_PROC=y > # CONFIG_UTS_NS is not set > # CONFIG_PID_NS is not set > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_PERF_EVENTS=y > # CONFIG_COMPAT_BRK is not set > CONFIG_KPROBES=y > diff --git a/arch/arc/configs/tb10x_defconfig b/arch/arc/configs/tb10x_defconfig > index dc739bd093e3..3a138f8c7299 100644 > --- a/arch/arc/configs/tb10x_defconfig > +++ b/arch/arc/configs/tb10x_defconfig > @@ -14,6 +14,7 @@ CONFIG_INITRAMFS_SOURCE="../tb10x-rootfs.cpio" > CONFIG_INITRAMFS_ROOT_UID=2100 > CONFIG_INITRAMFS_ROOT_GID=501 > # CONFIG_RD_GZIP is not set > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_SYSCTL_SYSCALL=y > CONFIG_KALLSYMS_ALL=y > # CONFIG_AIO is not set > diff --git a/arch/arc/configs/vdk_hs38_defconfig b/arch/arc/configs/vdk_hs38_defconfig > index 0c3b21416819..d7c858df520c 100644 > --- a/arch/arc/configs/vdk_hs38_defconfig > +++ b/arch/arc/configs/vdk_hs38_defconfig > @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/arch/arc/configs/vdk_hs38_smp_defconfig b/arch/arc/configs/vdk_hs38_smp_defconfig > index f9ad9d3ee702..015c1d43889e 100644 > --- a/arch/arc/configs/vdk_hs38_smp_defconfig > +++ b/arch/arc/configs/vdk_hs38_smp_defconfig > @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y > CONFIG_IKCONFIG=y > CONFIG_IKCONFIG_PROC=y > CONFIG_BLK_DEV_INITRD=y > +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y > CONFIG_EMBEDDED=y > CONFIG_PERF_EVENTS=y > # CONFIG_VM_EVENT_COUNTERS is not set > diff --git a/init/Kconfig b/init/Kconfig > index 149efd82447f..92118505dd33 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1209,14 +1209,22 @@ choice > default CC_OPTIMIZE_FOR_PERFORMANCE > > config CC_OPTIMIZE_FOR_PERFORMANCE > - bool "Optimize for performance" > + bool "Optimize for performance (-O2)" > help > This is the default optimization level for the kernel, building > with the "-O2" compiler flag for best performance and most > helpful compile-time warnings. > > +config CC_OPTIMIZE_FOR_PERFORMANCE_O3 > + bool "Optimize more for performance (-O3)" > + depends on ARC > + imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives > + help > + Choosing this option will pass "-O3" to your compiler to optimize > + the kernel yet more for performance. > + > config CC_OPTIMIZE_FOR_SIZE > - bool "Optimize for size" > + bool "Optimize for size (-Os)" > imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives > help > Choosing this option will pass "-Os" to your compiler resulting >
On Sat, Aug 31, 2019 at 1:43 AM Vineet Gupta <vineetg76@gmail.com> wrote: > > On 8/20/19 10:09 AM, Masahiro Yamada wrote: > > arch/arc/Makefile overrides -O2 with -O3. This is the only user of > > ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS. > > My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC > > Makefile. > > Why, it seems like a good generic facility for arches to over-ride stuff > (specially adding any toggles at the end of cmdline). > > And even if there are no current users, it would be good to have. I understand we > don't keep code for future, but strictly this is meta-code ;-) We can re-add it whenever we need it. > > Currently, ARC has no way to enable -Wmaybe-uninitialized because both > > -O3 and -Os disable it. Enabling it will be useful for compile-testing. > > This commit allows allmodconfig (, which defaults to -O2) to enable it. > > But this is a separate issue and was done on purpose because of unbearable build > spew at the time. As an experiment I enabled it in current kernel and at -O3 we > still get the dreaded spew in net/sunrpc/xdr.c and some more in net/ipv4. The spew > doesn't happen at -O2 and seems not ARC specific as I can see this with ARM -O3 > build with gcc 7.3 (buildroot 2018.08) > > | $ make ARCH=arm CROSS_COMPILE=arm-linux- net > | ...... > | ...... > | ../net/sunrpc/xdr.c: In function ‘xdr_encode_word’: > | ../net/sunrpc/xdr.c:1199:2: warning: ‘subbuf.tail[0].iov_base’ may be used > | uninitialized in this function [-Wmaybe-uninitialized] > | memcpy(subbuf->tail[0].iov_base, obj, this_len); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > | ../net/sunrpc/xdr.c:1205:17: note: ‘subbuf.tail[0].iov_base’ was declared here > | struct xdr_buf subbuf; > > > I understand the value of this toggle, but the spew is too much and at times > obfuscated likely other real issues. > > Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files > > in arch/arc/configs/ in order to keep the current config settings. > > My first reaction to adding this to all defconfigs was that this was inelegant : > for lack of better word :-) > > But indeed it seems better this way as we can now experiment with -O2 vs. -O3 from > config, rather than hardwiring to -O3. > > So if you could please split out the Wmaybe-uninitialized change I could not understand your request. I added 'imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED' for CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3. I cannot split it out. Otherwise, you will see false-positive maybe-uninitialized warnings. > Acked-by: Vineet Gupta <vgupta@synopsys.com> Thanks.
On 9/3/19 8:08 AM, Masahiro Yamada wrote: >> So if you could please split out the Wmaybe-uninitialized change > I could not understand your request. > > I added 'imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED' > for CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3. > > I cannot split it out. Otherwise, you will see false-positive > maybe-uninitialized warnings. Sorry I must have overlooked this part. So no issues now ! Thx, -Vineet
diff --git a/Makefile b/Makefile index bc55f366677d..891e47da503f 100644 --- a/Makefile +++ b/Makefile @@ -716,10 +716,12 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) -ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE -KBUILD_CFLAGS += -Os -else -KBUILD_CFLAGS += -O2 +ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE +KBUILD_CFLAGS += -O2 +else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 +KBUILD_CFLAGS += -O3 +else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE +KBUILD_CFLAGS += -Os endif ifdef CONFIG_CC_DISABLE_WARN_MAYBE_UNINITIALIZED diff --git a/arch/arc/Makefile b/arch/arc/Makefile index ee6d1184c2b1..f1c44cccf8d6 100644 --- a/arch/arc/Makefile +++ b/arch/arc/Makefile @@ -48,14 +48,6 @@ endif cfi := $(call as-instr,.cfi_startproc\n.cfi_endproc,-DARC_DW2_UNWIND_AS_CFI) cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi) -ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE -# Generic build system uses -O2, we want -O3 -# Note: No need to add to cflags-y as that happens anyways -# -# Disable the false maybe-uninitialized warings gcc spits out at -O3 -ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,) -endif - # small data is default for elf32 tool-chain. If not usable, disable it # This also allows repurposing GP as scratch reg to gcc reg allocator disable_small_data := y diff --git a/arch/arc/configs/axs101_defconfig b/arch/arc/configs/axs101_defconfig index e31a8ebc3ecc..0016149f9583 100644 --- a/arch/arc/configs/axs101_defconfig +++ b/arch/arc/configs/axs101_defconfig @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/axs103_defconfig b/arch/arc/configs/axs103_defconfig index e0e8567f0d75..5b031582a1cf 100644 --- a/arch/arc/configs/axs103_defconfig +++ b/arch/arc/configs/axs103_defconfig @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/axs103_smp_defconfig b/arch/arc/configs/axs103_smp_defconfig index fcbc952bc75b..d4eec39e0112 100644 --- a/arch/arc/configs/axs103_smp_defconfig +++ b/arch/arc/configs/axs103_smp_defconfig @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/haps_hs_defconfig b/arch/arc/configs/haps_hs_defconfig index 436f2135bdc1..47ff8a97e42d 100644 --- a/arch/arc/configs/haps_hs_defconfig +++ b/arch/arc/configs/haps_hs_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EXPERT=y CONFIG_PERF_EVENTS=y # CONFIG_COMPAT_BRK is not set diff --git a/arch/arc/configs/haps_hs_smp_defconfig b/arch/arc/configs/haps_hs_smp_defconfig index 33a787c375e2..9685fd5f57a4 100644 --- a/arch/arc/configs/haps_hs_smp_defconfig +++ b/arch/arc/configs/haps_hs_smp_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/hsdk_defconfig b/arch/arc/configs/hsdk_defconfig index 403125d9c9a3..9b9a74444ce2 100644 --- a/arch/arc/configs/hsdk_defconfig +++ b/arch/arc/configs/hsdk_defconfig @@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y CONFIG_BLK_DEV_RAM=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/nps_defconfig b/arch/arc/configs/nps_defconfig index f0a077c00efa..5978d4d7d5b0 100644 --- a/arch/arc/configs/nps_defconfig +++ b/arch/arc/configs/nps_defconfig @@ -6,6 +6,7 @@ CONFIG_HIGH_RES_TIMERS=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_SYSCTL_SYSCALL=y # CONFIG_EPOLL is not set # CONFIG_SIGNALFD is not set diff --git a/arch/arc/configs/nsim_700_defconfig b/arch/arc/configs/nsim_700_defconfig index de398c7b10b3..2b9b11474640 100644 --- a/arch/arc/configs/nsim_700_defconfig +++ b/arch/arc/configs/nsim_700_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_KALLSYMS_ALL=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y diff --git a/arch/arc/configs/nsim_hs_defconfig b/arch/arc/configs/nsim_hs_defconfig index 2dbd34a9ff07..bab3dd255841 100644 --- a/arch/arc/configs/nsim_hs_defconfig +++ b/arch/arc/configs/nsim_hs_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_KALLSYMS_ALL=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y diff --git a/arch/arc/configs/nsim_hs_smp_defconfig b/arch/arc/configs/nsim_hs_smp_defconfig index c7135f1e2583..90d2d50fb8dc 100644 --- a/arch/arc/configs/nsim_hs_smp_defconfig +++ b/arch/arc/configs/nsim_hs_smp_defconfig @@ -8,6 +8,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_KALLSYMS_ALL=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y diff --git a/arch/arc/configs/nsimosci_defconfig b/arch/arc/configs/nsimosci_defconfig index 385a71d3c478..5dd470b6609e 100644 --- a/arch/arc/configs/nsimosci_defconfig +++ b/arch/arc/configs/nsimosci_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_KALLSYMS_ALL=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y diff --git a/arch/arc/configs/nsimosci_hs_defconfig b/arch/arc/configs/nsimosci_hs_defconfig index 248a2c3bdc12..3532e86f7bff 100644 --- a/arch/arc/configs/nsimosci_hs_defconfig +++ b/arch/arc/configs/nsimosci_hs_defconfig @@ -10,6 +10,7 @@ CONFIG_NAMESPACES=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_KALLSYMS_ALL=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y diff --git a/arch/arc/configs/nsimosci_hs_smp_defconfig b/arch/arc/configs/nsimosci_hs_smp_defconfig index 1a4bc7b660fb..d90448bee064 100644 --- a/arch/arc/configs/nsimosci_hs_smp_defconfig +++ b/arch/arc/configs/nsimosci_hs_smp_defconfig @@ -8,6 +8,7 @@ CONFIG_IKCONFIG_PROC=y # CONFIG_UTS_NS is not set # CONFIG_PID_NS is not set CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_PERF_EVENTS=y # CONFIG_COMPAT_BRK is not set CONFIG_KPROBES=y diff --git a/arch/arc/configs/tb10x_defconfig b/arch/arc/configs/tb10x_defconfig index dc739bd093e3..3a138f8c7299 100644 --- a/arch/arc/configs/tb10x_defconfig +++ b/arch/arc/configs/tb10x_defconfig @@ -14,6 +14,7 @@ CONFIG_INITRAMFS_SOURCE="../tb10x-rootfs.cpio" CONFIG_INITRAMFS_ROOT_UID=2100 CONFIG_INITRAMFS_ROOT_GID=501 # CONFIG_RD_GZIP is not set +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_SYSCTL_SYSCALL=y CONFIG_KALLSYMS_ALL=y # CONFIG_AIO is not set diff --git a/arch/arc/configs/vdk_hs38_defconfig b/arch/arc/configs/vdk_hs38_defconfig index 0c3b21416819..d7c858df520c 100644 --- a/arch/arc/configs/vdk_hs38_defconfig +++ b/arch/arc/configs/vdk_hs38_defconfig @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/arch/arc/configs/vdk_hs38_smp_defconfig b/arch/arc/configs/vdk_hs38_smp_defconfig index f9ad9d3ee702..015c1d43889e 100644 --- a/arch/arc/configs/vdk_hs38_smp_defconfig +++ b/arch/arc/configs/vdk_hs38_smp_defconfig @@ -4,6 +4,7 @@ CONFIG_HIGH_RES_TIMERS=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_BLK_DEV_INITRD=y +CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y CONFIG_EMBEDDED=y CONFIG_PERF_EVENTS=y # CONFIG_VM_EVENT_COUNTERS is not set diff --git a/init/Kconfig b/init/Kconfig index 149efd82447f..92118505dd33 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1209,14 +1209,22 @@ choice default CC_OPTIMIZE_FOR_PERFORMANCE config CC_OPTIMIZE_FOR_PERFORMANCE - bool "Optimize for performance" + bool "Optimize for performance (-O2)" help This is the default optimization level for the kernel, building with the "-O2" compiler flag for best performance and most helpful compile-time warnings. +config CC_OPTIMIZE_FOR_PERFORMANCE_O3 + bool "Optimize more for performance (-O3)" + depends on ARC + imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives + help + Choosing this option will pass "-O3" to your compiler to optimize + the kernel yet more for performance. + config CC_OPTIMIZE_FOR_SIZE - bool "Optimize for size" + bool "Optimize for size (-Os)" imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives help Choosing this option will pass "-Os" to your compiler resulting
arch/arc/Makefile overrides -O2 with -O3. This is the only user of ARCH_CFLAGS. There is no user of ARCH_CPPFLAGS or ARCH_AFLAGS. My plan is to remove ARCH_{CPP,A,C}FLAGS after refactoring the ARC Makefile. Currently, ARC has no way to enable -Wmaybe-uninitialized because both -O3 and -Os disable it. Enabling it will be useful for compile-testing. This commit allows allmodconfig (, which defaults to -O2) to enable it. Add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y to all the defconfig files in arch/arc/configs/ in order to keep the current config settings. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- Makefile | 10 ++++++---- arch/arc/Makefile | 8 -------- arch/arc/configs/axs101_defconfig | 1 + arch/arc/configs/axs103_defconfig | 1 + arch/arc/configs/axs103_smp_defconfig | 1 + arch/arc/configs/haps_hs_defconfig | 1 + arch/arc/configs/haps_hs_smp_defconfig | 1 + arch/arc/configs/hsdk_defconfig | 1 + arch/arc/configs/nps_defconfig | 1 + arch/arc/configs/nsim_700_defconfig | 1 + arch/arc/configs/nsim_hs_defconfig | 1 + arch/arc/configs/nsim_hs_smp_defconfig | 1 + arch/arc/configs/nsimosci_defconfig | 1 + arch/arc/configs/nsimosci_hs_defconfig | 1 + arch/arc/configs/nsimosci_hs_smp_defconfig | 1 + arch/arc/configs/tb10x_defconfig | 1 + arch/arc/configs/vdk_hs38_defconfig | 1 + arch/arc/configs/vdk_hs38_smp_defconfig | 1 + init/Kconfig | 12 ++++++++++-- 19 files changed, 32 insertions(+), 14 deletions(-)