this_cpu_ptr is faster than per_cpu_ptr(p, smp_processor_id()). The latter helper needs to find the offset for current cpu, and needs more assembler instructions which objdump shows in following.
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 $ git diff --stat a932657f51eadb8280166e82dc7034dfbff3985a.. drivers/clocksource/arm_generic.c | 2 +- include/trace/ftrace.h | 4 +--- kernel/padata.c | 2 +- kernel/rcutree.c | 2 +- kernel/trace/blktrace.c | 2 +- kernel/trace/trace.c | 2 +- net/core/flow.c | 4 +--- net/openvswitch/datapath.c | 4 ++-- net/openvswitch/vport.c | 5 ++--- net/rds/ib_recv.c | 2 +- net/xfrm/xfrm_ipcomp.c | 7 +++---- 11 files changed, 15 insertions(+), 21 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
