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Why is there high CPU usage after inserting the leap second?

Updated 2013-02-21T10:33:23+00:00

Issue

  • After the insertion of the leap second several processes, notably java, were reporting a high CPU usage.
  • Logged messages shows back trace from ktime_get:
Jul  1 02:23:12 server kernel: [1121001.934357] INFO: task java:60028 blocked for more than 120 seconds.
Jul  1 02:23:12 server kernel: [1121001.937203] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jul  1 02:23:12 server kernel: [1121001.940147] java          D 0000000000000007     0 60028      1 0x00000080
Jul  1 02:23:12 server kernel: [1121001.943176]  ffff880d775419c8 0000000000000082 0000000501bfe000 ffffc900180cb058
Jul  1 02:23:12 server kernel: [1121001.946293]  ffffc900180cb020 ffffea002b821aa0 ffff880d34fe9580 000000d00002dc40
Jul  1 02:23:12 server kernel: [1121001.949488]  ffff880d34fe9b38 ffff880d77541fd8 000000000000f4e8 ffff880d34fe9b38
Jul  1 02:23:12 server kernel: [1121001.952757] Call Trace:
Jul  1 02:23:12 server kernel: [1121001.956042]  [<ffffffff8109b949>] ? ktime_get_ts+0xa9/0xe0
Jul  1 02:23:21 server kernel: [1121001.959347]  [<ffffffffa04bac10>] ? nfs_wait_bit_uninterruptible+0x0/0x20 [nfs]
Jul  1 02:23:21 server kernel: [1121001.962724]  [<ffffffff814ed833>] io_schedule+0x73/0xc0
Jul  1 02:23:21 server kernel: [1121001.966138]  [<ffffffffa04bac1e>] nfs_wait_bit_uninterruptible+0xe/0x20 [nfs]
Jul  1 02:23:21 server kernel: [1121001.969643]  [<ffffffff814ee1ef>] __wait_on_bit+0x5f/0x90
Jul  1 02:23:21 server kernel: [1121001.973190]  [<ffffffffa04bac10>] ? nfs_wait_bit_uninterruptible+0x0/0x20 [nfs]
Jul  1 02:23:21 server kernel: [1121001.976738]  [<ffffffff814ee298>] out_of_line_wait_on_bit+0x78/0x90
Jul  1 02:23:21 server kernel: [1121001.980253]  [<ffffffff81090d70>] ? wake_bit_function+0x0/0x50
Jul  1 02:23:21 server kernel: [1121001.983813]  [<ffffffff81110b6e>] ? find_get_page+0x1e/0xa0
Jul  1 02:23:21 server kernel: [1121001.987403]  [<ffffffffa04babff>] nfs_wait_on_request+0x2f/0x40 [nfs]
Jul  1 02:23:21 server kernel: [1121001.990991]  [<ffffffffa04c145e>] nfs_updatepage+0x28e/0x590 [nfs]
Jul  1 02:23:21 server kernel: [1121001.994526]  [<ffffffffa04af5c2>] nfs_write_end+0x152/0x2b0 [nfs]
Jul  1 02:23:21 server kernel: [1121001.998009]  [<ffffffff811116c4>] generic_file_buffered_write+0x174/0x2a0
Jul  1 02:23:21 server kernel: [1121002.001488]  [<ffffffff81112fb0>] __generic_file_aio_write+0x250/0x480
Jul  1 02:23:21 server kernel: [1121002.004944]  [<ffffffff8111324f>] generic_file_aio_write+0x6f/0xe0
Jul  1 02:23:21 server kernel: [1121002.008370]  [<ffffffffa04aeffe>] nfs_file_write+0xde/0x1f0 [nfs]
Jul  1 02:23:21 server kernel: [1121002.011760]  [<ffffffff8117661a>] do_sync_write+0xfa/0x140
Jul  1 02:23:21 server kernel: [1121002.015276]  [<ffffffff81090d30>] ? autoremove_wake_function+0x0/0x40
Jul  1 02:23:21 server kernel: [1121002.018657]  [<ffffffff8120c646>] ? security_file_permission+0x16/0x20
Jul  1 02:23:21 server kernel: [1121002.022012]  [<ffffffff81176918>] vfs_write+0xb8/0x1a0
Jul  1 02:23:21 server kernel: [1121002.025341]  [<ffffffff810d4932>] ? audit_syscall_entry+0x272/0x2a0
Jul  1 02:23:21 server kernel: [1121002.028661]  [<ffffffff81177321>] sys_write+0x51/0x90
Jul  1 02:23:21 server kernel: [1121002.031953]  [<ffffffff8100b0f2>] system_call_fastpath+0x16/0x1b

Environment

  • Red Hat Enterprise Linux 6 GA
  • Red Hat Enterprise Linux 6.1
  • Red Hat Enterprise Linux 6.2
  • Red Hat Enterprise Linux 6.3

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