We must ensure that the following four instructions are cache-aligned. Otherwise, it will cause problems with the performance of libMicro pread. 1: # uao_user_alternative 9f, str, sttr, xzr, x0, 8 str xzr, [x0], #8 nop subs x1, x1, #8 b.pl 1b with this patch: prc thr usecs/call samples errors cnt/samp size pread_z100 1 1 5.88400 807 0 1 102400 The result of pread can range from 5 to 9 depending on the alignment performance of this function. Cheng Jian (1): lib/clear_user: ensure loop in __arch_clear_user cache-aligned v2 Yang Yingliang (1): config: enable CONFIG_CLEAR_USER_WORKAROUND by default arch/arm64/Kconfig | 7 +++++++ arch/arm64/configs/openeuler_defconfig | 1 + arch/arm64/lib/clear_user.S | 3 +++ 3 files changed, 11 insertions(+) -- 2.25.1