Re: [LKP] [lkp] [locks] 7f3697e24d: +35.1% will-it-scale.per_thread_ops

[Huang\, Ying]

Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx> writes:

> On Fri, 29 Jan 2016 09:32:19 +0800
> kernel test robot <ying.huang@xxxxxxxxxxxxxxx> wrote:
>
>> FYI, we noticed the below changes on
>> 
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> commit 7f3697e24dc3820b10f445a4a7d914fc356012d1 ("locks: fix unlock when fcntl_setlk races with a close")
>> 
>> 
>> =========================================================================================
>> compiler/cpufreq_governor/kconfig/rootfs/tbox_group/test/testcase:
>>   gcc-4.9/performance/x86_64-rhel/debian-x86_64-2015-02-07.cgz/lkp-snb01/lock1/will-it-scale
>> 
>> commit: 
>>   9189922675ecca0fab38931d86b676e9d79602dc
>>   7f3697e24dc3820b10f445a4a7d914fc356012d1
>> 
>> 9189922675ecca0f 7f3697e24dc3820b10f445a4a7 
>> ---------------- -------------------------- 
>>          %stddev     %change         %stddev
>>              \          |                \  
>>    2376432 Â  0%      +2.1%    2427484 Â  0%  will-it-scale.per_process_ops
>>     807889 Â  0%     +35.1%    1091496 Â  4%  will-it-scale.per_thread_ops
>>      22.08 Â  2%     +89.1%      41.75 Â  5%  will-it-scale.time.user_time
>>    1238371 Â 14%    +100.4%    2481345 Â 39%  cpuidle.C1E-SNB.time
>>       3098 Â 57%     -66.6%       1035 Â171%  numa-numastat.node1.other_node
>>     379.25 Â  8%     -21.4%     298.00 Â 12%  numa-vmstat.node0.nr_alloc_batch
>>      22.08 Â  2%     +89.1%      41.75 Â  5%  time.user_time
>>       1795 Â  4%      +7.5%       1930 Â  2%  vmstat.system.cs
>>       0.54 Â  5%    +136.9%       1.28 Â 10%  perf-profile.cycles.___might_sleep.__might_sleep.kmem_cache_alloc.locks_alloc_lock.__posix_lock_file
>>       1.65 Â 57%    +245.2%       5.70 Â 29%  perf-profile.cycles.__fdget_raw.sys_fcntl.entry_SYSCALL_64_fastpath
>>       1.58 Â 59%    +248.3%       5.50 Â 31%  perf-profile.cycles.__fget.__fget_light.__fdget_raw.sys_fcntl.entry_SYSCALL_64_fastpath
>>       1.62 Â 58%    +246.3%       5.63 Â 30%  perf-profile.cycles.__fget_light.__fdget_raw.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%       5.88 Â 11%  perf-profile.cycles.__memset.locks_alloc_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       2.50 Â  2%    -100.0%       0.00 Â -1%  perf-profile.cycles.__memset.locks_alloc_lock.__posix_lock_file.vfs_lock_file.fcntl_setlk
>>       1.29 Â  4%    +138.8%       3.09 Â 11%  perf-profile.cycles.__memset.locks_alloc_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.47 Â  9%    +144.4%       1.16 Â 11%  perf-profile.cycles.__might_fault.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.37 Â 12%    +140.3%       0.90 Â  9%  perf-profile.cycles.__might_sleep.__might_fault.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.86 Â  6%    +137.7%       2.05 Â 10%  perf-profile.cycles.__might_sleep.kmem_cache_alloc.locks_alloc_lock.__posix_lock_file.vfs_lock_file
>>       0.61 Â 14%     +56.8%       0.95 Â 14%  perf-profile.cycles.__might_sleep.kmem_cache_alloc.locks_alloc_lock.fcntl_setlk.sys_fcntl
>>       0.00 Â -1%      +Inf%      39.84 Â 12%  perf-profile.cycles.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk.sys_fcntl
>>      16.44 Â  3%    -100.0%       0.00 Â -1%  perf-profile.cycles.__posix_lock_file.vfs_lock_file.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%       1.77 Â 11%  perf-profile.cycles._raw_spin_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>      59.34 Â  1%     -72.4%      16.36 Â 33%  perf-profile.cycles._raw_spin_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.46 Â 11%    +144.9%       1.13 Â 19%  perf-profile.cycles.avc_has_perm.inode_has_perm.file_has_perm.selinux_file_fcntl.security_file_fcntl
>>       0.87 Â  6%    +103.2%       1.77 Â 12%  perf-profile.cycles.avc_has_perm.inode_has_perm.file_has_perm.selinux_file_lock.security_file_lock
>>       0.81 Â  4%    +135.7%       1.90 Â 10%  perf-profile.cycles.copy_user_generic_string.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%      41.86 Â 12%  perf-profile.cycles.do_lock_file_wait.part.29.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.88 Â  6%    +127.8%       2.00 Â  9%  perf-profile.cycles.entry_SYSCALL_64
>>       0.86 Â  4%    +122.6%       1.92 Â 12%  perf-profile.cycles.entry_SYSCALL_64_after_swapgs
>>      84.98 Â  0%      -9.1%      77.20 Â  2%  perf-profile.cycles.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.76 Â 10%    +142.1%       1.84 Â 14%  perf-profile.cycles.file_has_perm.selinux_file_fcntl.security_file_fcntl.sys_fcntl.entry_SYSCALL_64_fastpath
>>       1.35 Â  4%    +106.3%       2.78 Â 11%  perf-profile.cycles.file_has_perm.selinux_file_lock.security_file_lock.fcntl_setlk.sys_fcntl
>>       0.00 Â -1%      +Inf%       0.89 Â 12%  perf-profile.cycles.flock_to_posix_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       6.90 Â  4%     -48.6%       3.55 Â 27%  perf-profile.cycles.fput.entry_SYSCALL_64_fastpath
>>       0.51 Â 10%    +140.5%       1.23 Â 16%  perf-profile.cycles.inode_has_perm.isra.31.file_has_perm.selinux_file_fcntl.security_file_fcntl.sys_fcntl
>>       0.98 Â  4%     +97.7%       1.93 Â 11%  perf-profile.cycles.inode_has_perm.isra.31.file_has_perm.selinux_file_lock.security_file_lock.fcntl_setlk
>>       0.00 Â -1%      +Inf%       6.56 Â 10%  perf-profile.cycles.kmem_cache_alloc.locks_alloc_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       2.75 Â  4%    -100.0%       0.00 Â -1%  perf-profile.cycles.kmem_cache_alloc.locks_alloc_lock.__posix_lock_file.vfs_lock_file.fcntl_setlk
>>       1.53 Â  7%    +119.7%       3.37 Â 13%  perf-profile.cycles.kmem_cache_alloc.locks_alloc_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%       1.79 Â 11%  perf-profile.cycles.kmem_cache_free.locks_free_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       0.46 Â 14%    +257.0%       1.66 Â 11%  perf-profile.cycles.kmem_cache_free.locks_free_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.40 Â  7%    +158.6%       1.05 Â 17%  perf-profile.cycles.kmem_cache_free.locks_free_lock.locks_dispose_list.__posix_lock_file.vfs_lock_file
>>       0.00 Â -1%      +Inf%       0.96 Â 10%  perf-profile.cycles.lg_local_lock.locks_insert_lock_ctx.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       0.00 Â -1%      +Inf%      14.69 Â 10%  perf-profile.cycles.locks_alloc_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>       6.38 Â  3%    -100.0%       0.00 Â -1%  perf-profile.cycles.locks_alloc_lock.__posix_lock_file.vfs_lock_file.fcntl_setlk.sys_fcntl
>>       3.28 Â  6%    +127.1%       7.45 Â 12%  perf-profile.cycles.locks_alloc_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%       9.75 Â 13%  perf-profile.cycles.locks_delete_lock_ctx.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>       3.61 Â  1%    -100.0%       0.00 Â -1%  perf-profile.cycles.locks_delete_lock_ctx.__posix_lock_file.vfs_lock_file.fcntl_setlk.sys_fcntl
>>       0.00 Â -1%      +Inf%       1.84 Â 11%  perf-profile.cycles.locks_dispose_list.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>       0.00 Â -1%      +Inf%       2.42 Â 10%  perf-profile.cycles.locks_free_lock.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>       1.00 Â  3%    -100.0%       0.00 Â -1%  perf-profile.cycles.locks_free_lock.__posix_lock_file.vfs_lock_file.fcntl_setlk.sys_fcntl
>>       0.63 Â 11%    +224.1%       2.05 Â 10%  perf-profile.cycles.locks_free_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%       1.22 Â 14%  perf-profile.cycles.locks_free_lock.locks_dispose_list.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       0.00 Â -1%      +Inf%       6.17 Â 15%  perf-profile.cycles.locks_insert_lock_ctx.__posix_lock_file.vfs_lock_file.do_lock_file_wait.fcntl_setlk
>>       2.31 Â  6%    -100.0%       0.00 Â -1%  perf-profile.cycles.locks_insert_lock_ctx.__posix_lock_file.vfs_lock_file.fcntl_setlk.sys_fcntl
>>       0.00 Â -1%      +Inf%       8.96 Â 13%  perf-profile.cycles.locks_unlink_lock_ctx.locks_delete_lock_ctx.__posix_lock_file.vfs_lock_file.do_lock_file_wait
>>       3.27 Â  1%    -100.0%       0.00 Â -1%  perf-profile.cycles.locks_unlink_lock_ctx.locks_delete_lock_ctx.__posix_lock_file.vfs_lock_file.fcntl_setlk
>>      53.88 Â  1%     -79.7%      10.92 Â 46%  perf-profile.cycles.native_queued_spin_lock_slowpath._raw_spin_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       2.75 Â  0%    +183.3%       7.79 Â 13%  perf-profile.cycles.put_pid.locks_unlink_lock_ctx.locks_delete_lock_ctx.__posix_lock_file.vfs_lock_file
>>       1.11 Â  9%    +137.2%       2.63 Â 14%  perf-profile.cycles.security_file_fcntl.sys_fcntl.entry_SYSCALL_64_fastpath
>>       1.69 Â  4%    +118.2%       3.69 Â 11%  perf-profile.cycles.security_file_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.91 Â  9%    +139.0%       2.17 Â 14%  perf-profile.cycles.selinux_file_fcntl.security_file_fcntl.sys_fcntl.entry_SYSCALL_64_fastpath
>>       1.39 Â  4%    +114.6%       2.97 Â 10%  perf-profile.cycles.selinux_file_lock.security_file_lock.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>       0.00 Â -1%      +Inf%      41.12 Â 12%  perf-profile.cycles.vfs_lock_file.do_lock_file_wait.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>      17.04 Â  3%    -100.0%       0.00 Â -1%  perf-profile.cycles.vfs_lock_file.fcntl_setlk.sys_fcntl.entry_SYSCALL_64_fastpath
>>      34.75 Â148%    +132.4%      80.75 Â 82%  sched_debug.cfs_rq:/.load.8
>>      15.00 Â  9%    +198.3%      44.75 Â 72%  sched_debug.cfs_rq:/.load_avg.21
>>      25.00 Â 29%    +574.0%     168.50 Â 78%  sched_debug.cfs_rq:/.load_avg.9
>>      38.47 Â  5%     +29.1%      49.65 Â 26%  sched_debug.cfs_rq:/.load_avg.avg
>>      63.17 Â 10%     +44.3%      91.16 Â 36%  sched_debug.cfs_rq:/.load_avg.stddev
>>     893865 Â 12%     -12.5%     782455 Â  0%  sched_debug.cfs_rq:/.min_vruntime.25
>>      18.25 Â 26%     +52.1%      27.75 Â 25%  sched_debug.cfs_rq:/.runnable_load_avg.9
>>     -57635 Â-68%    -196.4%      55548 Â130%  sched_debug.cfs_rq:/.spread0.1
>>    -802264 Â-25%     -29.5%    -565458 Â-49%  sched_debug.cfs_rq:/.spread0.8
>>    -804662 Â-25%     -29.4%    -567811 Â-48%  sched_debug.cfs_rq:/.spread0.min
>>       1233 Â  5%     +30.9%       1614 Â 28%  sched_debug.cfs_rq:/.tg_load_avg.0
>>       1233 Â  5%     +30.9%       1614 Â 28%  sched_debug.cfs_rq:/.tg_load_avg.1
>>       1228 Â  5%     +30.3%       1601 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.10
>>       1228 Â  5%     +30.4%       1601 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.11
>>       1228 Â  5%     +30.3%       1601 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.12
>>       1229 Â  5%     +30.0%       1598 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.13
>>       1228 Â  5%     +30.1%       1598 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.14
>>       1229 Â  5%     +30.0%       1598 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.15
>>       1226 Â  5%     +30.3%       1598 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.16
>>       1226 Â  5%     +30.2%       1597 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.17
>>       1227 Â  5%     +30.1%       1595 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.18
>>       1227 Â  5%     +29.4%       1588 Â 26%  sched_debug.cfs_rq:/.tg_load_avg.19
>>       1233 Â  5%     +30.4%       1609 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.2
>>       1222 Â  5%     +29.9%       1587 Â 26%  sched_debug.cfs_rq:/.tg_load_avg.20
>>       1223 Â  5%     +24.2%       1519 Â 20%  sched_debug.cfs_rq:/.tg_load_avg.21
>>       1223 Â  5%     +23.8%       1515 Â 20%  sched_debug.cfs_rq:/.tg_load_avg.22
>>       1223 Â  5%     +23.9%       1515 Â 20%  sched_debug.cfs_rq:/.tg_load_avg.23
>>       1223 Â  5%     +23.9%       1515 Â 20%  sched_debug.cfs_rq:/.tg_load_avg.24
>>       1223 Â  5%     +23.5%       1511 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.25
>>       1224 Â  5%     +23.5%       1512 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.26
>>       1223 Â  5%     +23.1%       1506 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.27
>>       1223 Â  5%     +22.5%       1499 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.28
>>       1224 Â  5%     +22.5%       1499 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.29
>>       1233 Â  5%     +30.3%       1607 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.3
>>       1223 Â  5%     +22.2%       1495 Â 18%  sched_debug.cfs_rq:/.tg_load_avg.30
>>       1224 Â  5%     +22.0%       1493 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.31
>>       1234 Â  5%     +30.0%       1604 Â 28%  sched_debug.cfs_rq:/.tg_load_avg.4
>>       1233 Â  5%     +30.0%       1604 Â 28%  sched_debug.cfs_rq:/.tg_load_avg.5
>>       1231 Â  5%     +30.3%       1604 Â 28%  sched_debug.cfs_rq:/.tg_load_avg.6
>>       1233 Â  5%     +30.0%       1603 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.7
>>       1231 Â  5%     +30.1%       1601 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.8
>>       1228 Â  5%     +30.3%       1601 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.9
>>       1228 Â  5%     +27.8%       1569 Â 24%  sched_debug.cfs_rq:/.tg_load_avg.avg
>>       1246 Â  5%     +30.7%       1628 Â 27%  sched_debug.cfs_rq:/.tg_load_avg.max
>>       1212 Â  5%     +22.2%       1481 Â 19%  sched_debug.cfs_rq:/.tg_load_avg.min
>>      15.00 Â  9%    +198.3%      44.75 Â 72%  sched_debug.cfs_rq:/.tg_load_avg_contrib.21
>>      25.00 Â 29%    +574.0%     168.50 Â 78%  sched_debug.cfs_rq:/.tg_load_avg_contrib.9
>>      38.53 Â  5%     +29.0%      49.71 Â 26%  sched_debug.cfs_rq:/.tg_load_avg_contrib.avg
>>      63.34 Â 10%     +44.1%      91.30 Â 36%  sched_debug.cfs_rq:/.tg_load_avg_contrib.stddev
>>     532.25 Â  2%      +8.5%     577.50 Â  6%  sched_debug.cfs_rq:/.util_avg.15
>>     210.75 Â 14%     -14.4%     180.50 Â  4%  sched_debug.cfs_rq:/.util_avg.29
>>     450.00 Â 22%     +50.7%     678.00 Â 18%  sched_debug.cfs_rq:/.util_avg.9
>>     955572 Â  4%     -10.2%     857813 Â  5%  sched_debug.cpu.avg_idle.6
>>      23.99 Â 60%     -76.2%       5.71 Â 24%  sched_debug.cpu.clock.stddev
>>      23.99 Â 60%     -76.2%       5.71 Â 24%  sched_debug.cpu.clock_task.stddev
>>       2840 Â 37%     -47.4%       1492 Â 65%  sched_debug.cpu.curr->pid.25
>>      34.75 Â148%    +132.4%      80.75 Â 82%  sched_debug.cpu.load.8
>>      61776 Â  7%      -7.1%      57380 Â  0%  sched_debug.cpu.nr_load_updates.25
>>       6543 Â  2%     +20.4%       7879 Â  9%  sched_debug.cpu.nr_switches.0
>>       5256 Â 23%    +177.1%      14566 Â 52%  sched_debug.cpu.nr_switches.27
>>       7915 Â  3%      +8.7%       8605 Â  3%  sched_debug.cpu.nr_switches.avg
>>      -0.25 Â-519%   +1900.0%      -5.00 Â-24%  sched_debug.cpu.nr_uninterruptible.12
>>       2.00 Â 93%    -125.0%      -0.50 Â-300%  sched_debug.cpu.nr_uninterruptible.24
>>      17468 Â 14%    +194.3%      51413 Â 75%  sched_debug.cpu.sched_count.15
>>       2112 Â  2%     +20.8%       2552 Â 11%  sched_debug.cpu.sched_goidle.0
>>       2103 Â 34%    +219.0%       6709 Â 55%  sched_debug.cpu.sched_goidle.27
>>       3159 Â  3%      +8.2%       3418 Â  4%  sched_debug.cpu.sched_goidle.avg
>>       1323 Â 64%     -72.7%     361.50 Â 15%  sched_debug.cpu.ttwu_count.23
>>       3264 Â 12%     +94.4%       6347 Â 41%  sched_debug.cpu.ttwu_count.27
>>       3860 Â  3%      +9.0%       4208 Â  3%  sched_debug.cpu.ttwu_count.avg
>>       2358 Â  3%     +28.7%       3035 Â  9%  sched_debug.cpu.ttwu_local.0
>>       1110 Â 22%     +54.6%       1716 Â 28%  sched_debug.cpu.ttwu_local.27
>>       1814 Â  8%     +16.1%       2106 Â  5%  sched_debug.cpu.ttwu_local.stddev
>> 
>> 
>> lkp-snb01: Sandy Bridge-EP
>> Memory: 32G
>> 
>>                              will-it-scale.per_thread_ops
>> 
>>    1.2e+06 ++---------------------------------------------------------------+
>>            |                                  O                             |
>>   1.15e+06 O+O O   O O   O   O   O   O                                      |
>>    1.1e+06 ++                                                               |
>>            |     O             O   O   O O OO                               |
>>   1.05e+06 ++          O   O                                                |
>>      1e+06 ++                                                               |
>>            |                                                                |
>>     950000 ++                                                               |
>>     900000 ++                                                               |
>>            |                                                                |
>>     850000 ++                                                               |
>>     800000 *+*.*.*.*.*.*.*.*.*.*.*.*. .*.*. *.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*
>>            |                         *     *                                |
>>     750000 ++---------------------------------------------------------------+
>> 
>> 
>>                           will-it-scale.time.user_time
>> 
>>   50 ++---------------------------------------------------------------------+
>>      |                                                                      |
>>   45 ++         O   O   O    O   O          O                               |
>>      O O O    O                                                             |
>>      |     O          O        O   O O                                      |
>>   40 ++           O        O           O  O                                 |
>>      |                                                                      |
>>   35 ++                                                                     |
>>      |                                                                      |
>>   30 ++                                                                     |
>>      |                                                                      |
>>      |            *                                                         |
>>   25 ++          + +                                                        |
>>      *.*.*.*..*.*   *.*.*..*.*.*.*.*.*.*..*.*.*.*.*.*.*..*.*.*.*.*.*..*.*.*.*
>>   20 ++---------------------------------------------------------------------+
>> 
>> 
>> 	[*] bisect-good sample
>> 	[O] bisect-bad  sample
>> 
>> To reproduce:
>> 
>>         git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
>>         cd lkp-tests
>>         bin/lkp install job.yaml  # job file is attached in this email
>>         bin/lkp run     job.yaml
>> 
>> 
>> Disclaimer:
>> Results have been estimated based on internal Intel analysis and are provided
>> for informational purposes only. Any difference in system hardware or software
>> design or configuration may affect actual performance.
>> 
>> 
>> Thanks,
>> Ying Huang
>
> Thanks...
>
> Huh...I'm stumped on this one. If anything I would have expected better
> performance with this patch since we don't even take the file_lock or
> do the fcheck in the F_UNLCK codepath now, or when there is an error.
>
> I'll see if I can reproduce it on my own test rig, but I'd welcome
> ideas of where and how this performance regression could have crept in.

This is a performance increase instead of performance regression.

Best Regards,
Huang, Ying