On Wed, Sep 4, 2013 at 12:41 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
> On Tue, Sep 3, 2013 at 5:14 PM, Waiman Long <waiman.long@xxxxxx> wrote:
>> On 09/03/2013 02:01 AM, Ingo Molnar wrote:
>>>
>>> * Waiman Long<waiman.long@xxxxxx> wrote:
>>>
>>>> Yes, that patch worked. It eliminated the lglock as a bottleneck in the
>>>> AIM7 workload. The lg_global_lock did not show up in the perf profile,
>>>> whereas the lg_local_lock was only 0.07%.
>>>
>>> Just curious: what's the worst bottleneck now in the optimized kernel? :-)
>>>
>>> Thanks,
>>>
>>> Ingo
>>
>> With the following patches on v3.11:
>> 1. Linus's version of lockref patch
>> 2. Al's lglock patch
>> 3. My preliminary patch to convert prepend_path under RCU
>>
>
> With no reference where to get those patches, it's a bit hard to follow.
>
> I will try some perf benchmarking with the attached patch against
> Linux "WfW" edition.
>
Eat thiz...
$ cat /proc/version
Linux version 3.11.0-1-lockref-small (sedat.dilek@xxxxxxxxx@fambox)
(gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #1 SMP Wed Sep 4
00:53:25 CEST 2013
$ ~/src/linux-kernel/linux/tools/perf/perf stat --null --repeat 5
../scripts/t_lockref_from-linus
Total loops: 26786226
Total loops: 26970142
Total loops: 26593312
Total loops: 26885806
Total loops: 26944076
Performance counter stats for '../scripts/t_lockref_from-linus' (5 runs):
10,011755076 seconds time elapsed
( +- 0,10% )
$ sudo ~/src/linux-kernel/linux/tools/perf/perf record -e cycles:pp
../scripts/t_lockref_from-linus
Total loops: 26267751
[ perf record: Woken up 25 times to write data ]
[ perf record: Captured and wrote 6.112 MB perf.data (~267015 samples) ]
$ sudo ~/src/linux-kernel/linux/tools/perf/perf report -tui
Samples: 159K of event 'cycles:pp', Event count (approx.): 77088218721
12,52%uit_lockref_from-ui[kernel.kallsyms] ui[k] irq_ret.rn
4,37%uit_lockref_from-ui[kernel.kallsyms] ui[k] __ticket_spin_lock
4,18%uit_lockref_from-ui[kernel.kallsyms] ui[k] __acct_.pdate_integrals
3,90%uit_lockref_from-ui[kernel.kallsyms] ui[k] .ser_exit
3,17%uit_lockref_from-ui[kernel.kallsyms] ui[k] __d_look.p_rc.
3,14%uit_lockref_from-ui[kernel.kallsyms] ui[k] lockref_get_or_lock
3,01%uit_lockref_from-ui[kernel.kallsyms] ui[k] local_clock
2,72%uit_lockref_from-ui[kernel.kallsyms] ui[k] kmem_cache_alloc
2,54%uit_lockref_from-uilibc-2.15.so ui[.] __xstat64
2,45%uit_lockref_from-ui[kernel.kallsyms] ui[k] link_path_walk
2,23%uit_lockref_from-ui[kernel.kallsyms] ui[k] kmem_cache_free
1,90%uit_lockref_from-ui[kernel.kallsyms] ui[k] rc._eqs_exit_common.isra.43
1,88%uit_lockref_from-ui[kernel.kallsyms] ui[k] tracesys
1,82%uit_lockref_from-ui[kernel.kallsyms] ui[k] rc._eqs_enter_common.isra.45
1,77%uit_lockref_from-ui[kernel.kallsyms] ui[k] sched_clock_cp.
1,76%uit_lockref_from-ui[kernel.kallsyms] ui[k] .ser_enter
1,73%uit_lockref_from-ui[kernel.kallsyms] ui[k] lockref_p.t_or_lock
1,70%uit_lockref_from-ui[kernel.kallsyms] ui[k] path_look.pat
1,53%uit_lockref_from-ui[kernel.kallsyms] ui[k] native_read_tsc
1,52%uit_lockref_from-ui[kernel.kallsyms] ui[k] native_sched_clock
1,51%uit_lockref_from-ui[kernel.kallsyms] ui[k] cp_new_stat
1,51%uit_lockref_from-ui[kernel.kallsyms] ui[k] syscall_trace_enter
1,46%uit_lockref_from-ui[kernel.kallsyms] ui[k] acco.nt_system_time
1,42%uit_lockref_from-ui[kernel.kallsyms] ui[k] path_init
1,42%uit_lockref_from-ui[kernel.kallsyms] ui[k] copy_.ser_generic_.nrolled
1,39%uit_lockref_from-ui[kernel.kallsyms] ui[k] jiffies_to_timeval
1,39%uit_lockref_from-ui[kernel.kallsyms] ui[k] getname_flags
1,37%uit_lockref_from-ui[kernel.kallsyms] ui[k] vfs_getattr
1,25%uit_lockref_from-ui[kernel.kallsyms] ui[k] common_perm
1,14%uit_lockref_from-ui[kernel.kallsyms] ui[k] get_vtime_delta
1,13%uit_lockref_from-ui[kernel.kallsyms] ui[k] look.p_fast
1,12%uit_lockref_from-ui[kernel.kallsyms] ui[k] syscall_trace_leave
1,05%uit_lockref_from-ui[kernel.kallsyms] ui[k] system_call
0,99%uit_lockref_from-ui[kernel.kallsyms] ui[k] generic_fillattr
0,94%uit_lockref_from-ui[kernel.kallsyms] ui[k] .ser_path_at_empty
0,91%uit_lockref_from-ui[kernel.kallsyms] ui[k] acco.nt_.ser_time
0,90%uit_lockref_from-ui[kernel.kallsyms] ui[k] __ticket_spin_.nlock
0,87%uit_lockref_from-ui[kernel.kallsyms] ui[k] strncpy_from_.ser
0,83%uit_lockref_from-ui[kernel.kallsyms] ui[k] filename_look.p
0,82%uit_lockref_from-ui[kernel.kallsyms] ui[k] generic_permission
0,78%uit_lockref_from-ui[kernel.kallsyms] ui[k] complete_walk
0,75%uit_lockref_from-ui[kernel.kallsyms] ui[k] vfs_fstatat
0,74%uit_lockref_from-ui[kernel.kallsyms] ui[k] lg_local_lock
0,72%uit_lockref_from-ui[kernel.kallsyms] ui[k] vtime_acco.nt_.ser
0,67%uit_lockref_from-ui[kernel.kallsyms] ui[k] dp.t
0,66%uit_lockref_from-ui[kernel.kallsyms] ui[k] __inode_permission
0,62%uit_lockref_from-ui[kernel.kallsyms] ui[k] rc._eqs_enter
0,58%uit_lockref_from-ui[kernel.kallsyms] ui[k] lg_local_.nlock
0,56%uit_lockref_from-ui[kernel.kallsyms] ui[k] vtime_.ser_enter
0,50%uit_lockref_from-ui[kernel.kallsyms] ui[k] cp.acct_acco.nt_field
0,48%uit_lockref_from-ui[kernel.kallsyms] ui[k] sec.rity_inode_permission
0,48%uit_lockref_from-uit_lockref_from-lin.sui[.] start_ro.tine
0,47%uit_lockref_from-ui[kernel.kallsyms] ui[k] sec.rity_inode_getattr
0,47%uit_lockref_from-ui[kernel.kallsyms] ui[k] acct_acco.nt_cp.time
Press '?' for help on key bindings
Here the annotated entries for the first two entries:
irq_return
│
│
│
│ Disassembly of section .text:
│
│ ffffffff816d4f2c <irq_return>:
100,00 │ ↓ jmpq 120
│ data32 data32 data32 data32 nopw %cs:0x0(%rax,%rax,1)
__ticket_spin_lock
│
│
│
│ Disassembly of section .text:
│
│ ffffffff8104ff10 <__ticket_spin_lock>:
2,55 │ push %rbp
1,19 │ mov $0x10000,%eax
2,16 │ mov %rsp,%rbp
84,70 │ lock xadd %eax,(%rdi)
0,14 │ mov %eax,%edx
│ shr $0x10,%edx
4,33 │ cmp %ax,%dx
0,03 │ ↓ je 2a
│ nop
│20: pause
0,03 │ movzwl (%rdi),%eax
│ cmp %dx,%ax
│ ↑ jne 20
0,03 │2a: pop %rbp
4,84 │ ← retq
- Sedat -
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