diff options
| author | Peter Zijlstra | 2013-11-29 18:04:39 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2014-01-13 13:47:38 +0100 |
| commit | 5dd12c2152743747ca9f50ef80281e54cc416dc0 (patch) | |
| tree | 8fc200d8782c9b0871419891c838711db659e289 /arch/x86/include/asm/timer.h | |
| parent | 62b94a08da1bae9d187d49dfcd6665af393750f8 (diff) | |
sched/clock, x86: Use mul_u64_u32_shr() for native_sched_clock()
Use mul_u64_u32_shr() so that x86_64 can use a single 64x64->128 mul.
Before:
0000000000000560 <native_sched_clock>:
560: 44 8b 1d 00 00 00 00 mov 0x0(%rip),%r11d # 567 <native_sched_clock+0x7>
567: 55 push %rbp
568: 48 89 e5 mov %rsp,%rbp
56b: 45 85 db test %r11d,%r11d
56e: 75 4f jne 5bf <native_sched_clock+0x5f>
570: 0f 31 rdtsc
572: 89 c0 mov %eax,%eax
574: 48 c1 e2 20 shl $0x20,%rdx
578: 48 c7 c1 00 00 00 00 mov $0x0,%rcx
57f: 48 09 c2 or %rax,%rdx
582: 48 c7 c7 00 00 00 00 mov $0x0,%rdi
589: 65 8b 04 25 00 00 00 mov %gs:0x0,%eax
590: 00
591: 48 98 cltq
593: 48 8b 34 c5 00 00 00 mov 0x0(,%rax,8),%rsi
59a: 00
59b: 48 89 d0 mov %rdx,%rax
59e: 81 e2 ff 03 00 00 and $0x3ff,%edx
5a4: 48 c1 e8 0a shr $0xa,%rax
5a8: 48 0f af 14 0e imul (%rsi,%rcx,1),%rdx
5ad: 48 0f af 04 0e imul (%rsi,%rcx,1),%rax
5b2: 5d pop %rbp
5b3: 48 03 04 3e add (%rsi,%rdi,1),%rax
5b7: 48 c1 ea 0a shr $0xa,%rdx
5bb: 48 01 d0 add %rdx,%rax
5be: c3 retq
After:
0000000000000550 <native_sched_clock>:
550: 8b 3d 00 00 00 00 mov 0x0(%rip),%edi # 556 <native_sched_clock+0x6>
556: 55 push %rbp
557: 48 89 e5 mov %rsp,%rbp
55a: 48 83 e4 f0 and $0xfffffffffffffff0,%rsp
55e: 85 ff test %edi,%edi
560: 75 2c jne 58e <native_sched_clock+0x3e>
562: 0f 31 rdtsc
564: 89 c0 mov %eax,%eax
566: 48 c1 e2 20 shl $0x20,%rdx
56a: 48 09 c2 or %rax,%rdx
56d: 65 48 8b 04 25 00 00 mov %gs:0x0,%rax
574: 00 00
576: 89 c0 mov %eax,%eax
578: 48 f7 e2 mul %rdx
57b: 65 48 8b 0c 25 00 00 mov %gs:0x0,%rcx
582: 00 00
584: c9 leaveq
585: 48 0f ac d0 0a shrd $0xa,%rdx,%rax
58a: 48 01 c8 add %rcx,%rax
58d: c3 retq
MAINLINE POST
sched_clock_stable: 1 1
(cold) sched_clock: 329841 331312
(cold) local_clock: 301773 310296
(warm) sched_clock: 38375 38247
(warm) local_clock: 100371 102713
(warm) rdtsc: 27340 27289
sched_clock_stable: 0 0
(cold) sched_clock: 382634 372706
(cold) local_clock: 396890 399275
(warm) sched_clock: 38194 38124
(warm) local_clock: 143452 148698
(warm) rdtsc: 27345 27365
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-piu203ses5y1g36bnyw2n16x@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/timer.h')
| -rw-r--r-- | arch/x86/include/asm/timer.h | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/x86/include/asm/timer.h b/arch/x86/include/asm/timer.h index 34baa0eb5d0c..10a78c037910 100644 --- a/arch/x86/include/asm/timer.h +++ b/arch/x86/include/asm/timer.h @@ -4,6 +4,7 @@ #include <linux/pm.h> #include <linux/percpu.h> #include <linux/interrupt.h> +#include <linux/math64.h> #define TICK_SIZE (tick_nsec / 1000) @@ -57,10 +58,8 @@ DECLARE_PER_CPU(unsigned long long, cyc2ns_offset); static inline unsigned long long __cycles_2_ns(unsigned long long cyc) { - int cpu = smp_processor_id(); - unsigned long long ns = per_cpu(cyc2ns_offset, cpu); - ns += mult_frac(cyc, per_cpu(cyc2ns, cpu), - (1UL << CYC2NS_SCALE_FACTOR)); + unsigned long long ns = this_cpu_read(cyc2ns_offset); + ns += mul_u64_u32_shr(cyc, this_cpu_read(cyc2ns), CYC2NS_SCALE_FACTOR); return ns; } |