5.2同样，我们跟踪一下wirteback子系统的相关情况：

<SPAN style="FONT-SIZE: 14px">root@hyk-linux:/home/hyk/program/cprogram# perf record -e writeback:* lsa.out        cscope.po.out  perf.data.old  t2.c  test1     testperf
cscope.in.out  malloc.c       t1      tags  test1s    testperf.c
cscope.out     perf.data      t2      test  test.img
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.013 MB perf.data (~548 samples) ]
root@hyk-linux:/home/hyk/program/cprogram# perf report
# ========
# captured on: Mon Aug 26 08:59:58 2013
# hostname : hyk-linux
# os release : 3.10.9
# perf version : 3.10.9
# arch : i686
# nrcpus online : 4
# nrcpus avail : 4
# cpudesc : Intel(R) Core(TM) i5-2430M CPU @ 2.40GHz
# cpuid : GenuineIntel，6，42，7
# total memory : 4084184 kB
# cmdline : /media/usr/src/linux-3.10.9/tools/perf/perf record -e writeback:* ls
# event : name = writeback:writeback_dirty_page， type = 2， config = 0x291， confi
# event : name = writeback:writeback_dirty_inode_start， type = 2， config = 0x290
# event : name = writeback:writeback_dirty_inode， type = 2， config = 0x28f， conf
# event : name = writeback:writeback_write_inode_start， type = 2， config = 0x28e
# event : name = writeback:writeback_write_inode， type = 2， config = 0x28d， conf
# event : name = writeback:writeback_queue， type = 2， config = 0x28c， config1 =
# event : name = writeback:writeback_exec， type = 2， config = 0x28b， config1 = 0
# event : name = writeback:writeback_start， type = 2， config = 0x28a， config1 =
# event : name = writeback:writeback_written， type = 2， config = 0x289， config1
# event : name = writeback:writeback_wait， type = 2， config = 0x288， config1 = 0
# event : name = writeback:writeback_pages_written， type = 2， config = 0x287， co
# event : name = writeback:writeback_nowork， type = 2， config = 0x286， config1 =
# event : name = writeback:writeback_wake_background， type = 2， config = 0x285，
# event : name = writeback:writeback_bdi_register， type = 2， config = 0x284， con
# event : name = writeback:writeback_bdi_unregister， type = 2， config = 0x283， c
# event : name = writeback:wbc_writepage， type = 2， config = 0x282， config1 = 0x
# event : name = writeback:writeback_queue_io， type = 2， config = 0x281， config1
# event : name = writeback:global_dirty_state， type = 2， config = 0x280， config1
# event : name = writeback:bdi_dirty_ratelimit， type = 2， config = 0x27f， config
# event : name = writeback:balance_dirty_pages， type = 2， config = 0x27e， config
# event : name = writeback:writeback_sb_inodes_requeue， type = 2， config = 0x27d
# event : name = writeback:writeback_congestion_wait， type = 2， config = 0x27c，
# event : name = writeback:writeback_wait_iff_congested， type = 2， config = 0x27
# event : name = writeback:writeback_single_inode_start， type = 2， config = 0x27
# event : name = writeback:writeback_single_inode， type = 2， config = 0x279， con
# HEADER_CPU_TOPOLOGY info available， use -I to display
# pmu mappings: cpu = 4， software = 1， tracepoint = 2， uncore_cbox_0 = 6， uncore
# ========
#
# Samples: 0  of event 'writeback:writeback_dirty_page'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 1  of event 'writeback:writeback_dirty_inode_start'
# Event count (approx.): 1
#
# Overhead  Command      Shared Object                  Symbol
# ........  .......  .................  ......................
#
100.00%       ls  [kernel.kallsyms]  [k] __mark_inode_dirty
# Samples: 1  of event 'writeback:writeback_dirty_inode'
# Event count (approx.): 1
#
# Overhead  Command      Shared Object                  Symbol
# ........  .......  .................  ......................
#
100.00%       ls  [kernel.kallsyms]  [k] __mark_inode_dirty
# Samples: 0  of event 'writeback:writeback_write_inode_start'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_write_inode'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_queue'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_exec'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_start'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_written'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_wait'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_pages_written'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_nowork'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_wake_background'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_bdi_register'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_bdi_unregister'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:wbc_writepage'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_queue_io'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:global_dirty_state'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:bdi_dirty_ratelimit'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:balance_dirty_pages'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_sb_inodes_requeue'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
#
# Samples: 0  of event 'writeback:writeback_congestion_wait'
# Event count (approx.): 0
#
# Overhead  Command  Shared Object  Symbol
# ........  .......  .............  ......
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