>tytso@xxxxxxx wrote
>
>On Fri, Apr 09, 2010 at 05:48:23PM -0600, Chen, Tim C wrote:
>>
>> Your patch did remove the contention on the j_state_lock for dbench
>> in my testing with 64 threads. The contention point now
>> moves dcache_lock, which is also another tricky bottleneck.
>>
>> In our other testing with FFSB that creates/rename/remove a
>lot of directories,
>> we found that journal->j_revoke_lock was also heavily contended.
>>
>
>Do you have lock_stat reports handy? I'd love to take a look at them.
>
>Thanks,
>
Here's the lock_stat for dbench and ffsb respectively.
-- Tim
lock_stat for dbench:
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
dcache_lock: 6025583 6290348 0.11 19839.44 1798082999.37 6444352 6455257 0.09 1098.09 18850261.22
&(&vfsmount_lock)->rlock: 73901 76686 0.11 60.15 113381.57 1453130 1729218 0.11 77.81 1256803.55
&(&dentry->d_lock)->rlock: 70544 70816 0.10 81.63 57218.45 3260359 9367952 0.10 87.68 2882612.48
cpufreq_driver_lock: 13957 13957 0.15 16.34 11674.72 191861 191900 0.15 18.25 127363.61
&sb->s_type->i_mutex_key#6: 11469 11471 9.81 23837.58 15425101.39 19705 19832 0.99 12681.28 9526135.06
rcu_node_level_1: 6074 6078 0.14 119.79 61347.68 195893 526772 0.09 107.31 250906.16
&(&sbinfo->stat_lock)->rlock: 4119 4201 0.11 58.20 5152.25 170931 485773 0.10 74.01 171147.12
clockevents_lock: 1303 1323 0.15 48.76 5762.88 32798 53769 0.46 47.28 132041.92
tick_broadcast_lock: 1072 1077 0.16 44.15 3567.97 51339 71398 0.18 66.81 145312.14
inode_lock: 862 870 0.16 19.43 896.55 122469 189716 0.10 39.86 132519.21
lock_stat for ffsb:
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
&(&journal->j_revoke_lock)->rlock#2: 2776732 2797303 0.09 1226.54 25572406.37 5534106 7180109 0.08 940.11 4072313.72
&(&inode->i_data.private_lock)->rlock: 877686 881325 0.10 1012.54 6852161.82 3877066 5037811 0.08 953.17 2419421.96
clockevents_lock: 748984 760650 0.12 1863.26 101406877.20 1060958 1382494 0.42 1308.88 11071530.40
dcache_lock: 388413 409694 0.12 864.01 1468208.41 1434252 2471228 0.09 2655.71 2629938.50
&(&q->__queue_lock)->rlock: 211707 214131 0.11 813.65 1255954.31 464310 2882306 0.08 984.38 3729431.78
&(&journal->j_state_lock)->rlock#2: 206642 206832 0.13 2312.55 3561899.14 1049032 1490515 0.08 2447.20 2079827.95
&(&transaction->t_handle_lock)->rlo#2: 179770 180327 0.11 745.09 438500.40 1724000 1997981 0.08 795.20 1097502.30
&sbi->s_orphan_lock#2: 123150 123161 3.87 41421.17 406113809.87 408087 532092 0.17 36588.86 5151196.68
&(&n->list_lock)->rlock: 116548 117330 0.11 88.35 65548.86 2219789 4243060 0.08 87.43 1324289.71
&(&journal->j_list_lock)->rlock#2: 71612 72458 0.11 814.83 257968.30 833686 3148049 0.08 --
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