From 3938fa39fb263ffb23ec3f3f9c6849709fbeb469 Mon Sep 17 00:00:00 2001 From: Peter Jung Date: Sat, 20 Jan 2024 14:03:01 +0100 Subject: [PATCH] Add extra GCC optimization flags Enable 2 extra optimimization flags: -fivopts Perform induction variable optimizations (strength reduction, induction variable merging and induction variable elimination) on trees. -fmodulo-sched Perform swing modulo scheduling immediately before the first scheduling pass. This pass looks at innermost loops and reorders their instructions by overlapping different iterations. stress-ng microbenchmark improvements (average from 10 x 1min runs) on Alderlake with gcc 13.2.0: af-alg: 1.0% (kernel AF_ALG crypto) pipe: 1.5% (pipe + context switch) fork: 4.4% (process fork/exit) mmap: 3.0% (memory mapping) switch: 4.9% (context switching) KVM QEMU bootspeed improvements (based on average of 100 boots): 0.5% Signed-off-by: Peter Jung --- arch/x86/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index b7717a5e10ed..7302712d94e2 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -67,7 +67,7 @@ export BITS # # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 # -KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx +KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-avx2 -mno-avx512f -fno-tree-vectorize -fivopts -fmodulo-sched KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 ifeq ($(CONFIG_X86_KERNEL_IBT),y) -- 2.43.0