forked from Minki/linux
f7c83bcbfa
this_cpu_ptr/this_cpu_read is faster than per_cpu_ptr(p, smp_processor_id()) and can reduce memory accesses. The latter helper needs to find the offset for current cpu, and needs more assembler instructions which objdump shows in following. this_cpu_ptr relocates and address. this_cpu_read() relocates the address and performs the fetch. this_cpu_read() saves you more instructions since it can do the relocation and the fetch in one instruction. per_cpu_ptr(p, smp_processor_id())： 1e: 65 8b 04 25 00 00 00 00 mov %gs:0x0,%eax 26: 48 98 cltq 28: 31 f6 xor %esi,%esi 2a: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 31: 48 8b 04 c5 00 00 00 00 mov 0x0(,%rax,8),%rax 39: c7 44 10 04 14 00 00 00 movl $0x14,0x4(%rax,%rdx,1) this_cpu_ptr(p) 1e: 65 48 03 14 25 00 00 00 00 add %gs:0x0,%rdx 27: 31 f6 xor %esi,%esi 29: c7 42 04 14 00 00 00 movl $0x14,0x4(%rdx) 30: 48 c7 c7 00 00 00 00 mov $0x0,%rdi Signed-off-by: Shan Wei <davidshan@tencent.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> |
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| xfrm_algo.c | ||
| xfrm_hash.c | ||
| xfrm_hash.h | ||
| xfrm_input.c | ||
| xfrm_ipcomp.c | ||
| xfrm_output.c | ||
| xfrm_policy.c | ||
| xfrm_proc.c | ||
| xfrm_replay.c | ||
| xfrm_state.c | ||
| xfrm_sysctl.c | ||
| xfrm_user.c | ||