€•ð—      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ$/translations/zh_CN/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/zh_TW/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/it_IT/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/ja_JP/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/ko_KR/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/sp_SP/locking/lockstat”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒLock Statistics”h]”hŒLock Statistics”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒ>/var/lib/git/docbuild/linux/Documentation/locking/lockstat.rst”h Kubh¢)”}”(hhh]”(h§)”}”(hŒWhat”h]”hŒWhat”…””}”(hhºhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh·hžhhŸh¶h KubhŒ	paragraph”“”)”}”(hŒ6As the name suggests, it provides statistics on locks.”h]”hŒ6As the name suggests, it provides statistics on locks.”…””}”(hhÊhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubeh}”(h]”Œwhat”ah ]”h"]”Œwhat”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒWhy”h]”hŒWhy”…””}”(hhãhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hhàhžhhŸh¶h KubhÉ)”}”(hŒDBecause things like lock contention can severely impact performance.”h]”hŒDBecause things like lock contention can severely impact performance.”…””}”(hhñhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khhàhžhubeh}”(h]”Œwhy”ah ]”h"]”Œwhy”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒHow”h]”hŒHow”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h KubhÉ)”}”(hŒ÷Lockdep already has hooks in the lock functions and maps lock instances to
lock classes. We build on that (see Documentation/locking/lockdep-design.rst).
The graph below shows the relation between the lock functions and the various
hooks therein::”h]”hŒöLockdep already has hooks in the lock functions and maps lock instances to
lock classes. We build on that (see Documentation/locking/lockdep-design.rst).
The graph below shows the relation between the lock functions and the various
hooks therein:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khj  hžhubhŒliteral_block”“”)”}”(hX‘        __acquire
          |
         lock _____
          |        \
          |    __contended
          |         |
          |       <wait>
          | _______/
          |/
          |
     __acquired
          |
          .
        <hold>
          .
          |
     __release
          |
       unlock

lock, unlock  - the regular lock functions
__*           - the hooks
<>            - states”h]”hX‘        __acquire
          |
         lock _____
          |        \
          |    __contended
          |         |
          |       <wait>
          | _______/
          |/
          |
     __acquired
          |
          .
        <hold>
          .
          |
     __release
          |
       unlock

lock, unlock  - the regular lock functions
__*           - the hooks
<>            - states”…””}”hj(  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1j&  hŸh¶h Khj  hžhubhÉ)”}”(hŒ5With these hooks we provide the following statistics:”h]”hŒ5With these hooks we provide the following statistics:”…””}”(hj8  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K0hj  hžhubhŒblock_quote”“”)”}”(hXê  con-bounces
       - number of lock contention that involved x-cpu data
contentions
       - number of lock acquisitions that had to wait
wait time
    min
       - shortest (non-0) time we ever had to wait for a lock
    max
       - longest time we ever had to wait for a lock
    total
       - total time we spend waiting on this lock
    avg
       - average time spent waiting on this lock
acq-bounces
       - number of lock acquisitions that involved x-cpu data
acquisitions
       - number of times we took the lock
hold time
    min
       - shortest (non-0) time we ever held the lock
    max
       - longest time we ever held the lock
    total
       - total time this lock was held
    avg
       - average time this lock was held
”h]”hŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ@con-bounces
- number of lock contention that involved x-cpu data”h]”(hŒterm”“”)”}”(hŒcon-bounces”h]”hŒcon-bounces”…””}”(hjY  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K2hjS  ubhŒ
definition”“”)”}”(hhh]”hŒbullet_list”“”)”}”(hhh]”hŒ	list_item”“”)”}”(hŒ2number of lock contention that involved x-cpu data”h]”hÉ)”}”(hju  h]”hŒ2number of lock contention that involved x-cpu data”…””}”(hjw  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K3hjs  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjn  ubah}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1jl  hŸh¶h K3hji  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjS  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K2hjN  ubjR  )”}”(hŒ:contentions
- number of lock acquisitions that had to wait”h]”(jX  )”}”(hŒcontentions”h]”hŒcontentions”…””}”(hj¢  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K4hjž  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ,number of lock acquisitions that had to wait”h]”hÉ)”}”(hj¸  h]”hŒ,number of lock acquisitions that had to wait”…””}”(hjº  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K5hj¶  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj³  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K5hj°  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjž  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K4hjN  ubjR  )”}”(hŒáwait time
min
   - shortest (non-0) time we ever had to wait for a lock
max
   - longest time we ever had to wait for a lock
total
   - total time we spend waiting on this lock
avg
   - average time spent waiting on this lock”h]”(jX  )”}”(hŒ	wait time”h]”hŒ	wait time”…””}”(hjã  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K=hjß  ubjh  )”}”(hhh]”jM  )”}”(hhh]”(jR  )”}”(hŒ:min
- shortest (non-0) time we ever had to wait for a lock”h]”(jX  )”}”(hŒmin”h]”hŒmin”…””}”(hjû  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K7hj÷  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ4shortest (non-0) time we ever had to wait for a lock”h]”hÉ)”}”(hj  h]”hŒ4shortest (non-0) time we ever had to wait for a lock”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K8hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K8hj	  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj÷  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K7hjô  ubjR  )”}”(hŒ1max
- longest time we ever had to wait for a lock”h]”(jX  )”}”(hŒmax”h]”hŒmax”…””}”(hj<  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K9hj8  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ+longest time we ever had to wait for a lock”h]”hÉ)”}”(hjR  h]”hŒ+longest time we ever had to wait for a lock”…””}”(hjT  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K:hjP  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjM  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K:hjJ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj8  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K9hjô  ubjR  )”}”(hŒ0total
- total time we spend waiting on this lock”h]”(jX  )”}”(hŒtotal”h]”hŒtotal”…””}”(hj}  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K;hjy  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ(total time we spend waiting on this lock”h]”hÉ)”}”(hj“  h]”hŒ(total time we spend waiting on this lock”…””}”(hj•  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K<hj‘  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjŽ  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K<hj‹  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjy  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K;hjô  ubjR  )”}”(hŒ-avg
- average time spent waiting on this lock”h]”(jX  )”}”(hŒavg”h]”hŒavg”…””}”(hj¾  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K=hjº  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ'average time spent waiting on this lock”h]”hÉ)”}”(hjÔ  h]”hŒ'average time spent waiting on this lock”…””}”(hjÖ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K>hjÒ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjÏ  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K>hjÌ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjº  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K=hjô  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jL  hjñ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjß  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K=hjN  ubjR  )”}”(hŒBacq-bounces
- number of lock acquisitions that involved x-cpu data”h]”(jX  )”}”(hŒacq-bounces”h]”hŒacq-bounces”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h K?hj  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ4number of lock acquisitions that involved x-cpu data”h]”hÉ)”}”(hj'  h]”hŒ4number of lock acquisitions that involved x-cpu data”…””}”(hj)  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K@hj%  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj"  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h K@hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h K?hjN  ubjR  )”}”(hŒ/acquisitions
- number of times we took the lock”h]”(jX  )”}”(hŒacquisitions”h]”hŒacquisitions”…””}”(hjR  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KAhjN  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ number of times we took the lock”h]”hÉ)”}”(hjh  h]”hŒ number of times we took the lock”…””}”(hjj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KBhjf  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjc  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h KBhj`  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjN  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KAhjN  ubjR  )”}”(hŒ½hold time
min
   - shortest (non-0) time we ever held the lock
max
   - longest time we ever held the lock
total
   - total time this lock was held
avg
   - average time this lock was held
”h]”(jX  )”}”(hŒ	hold time”h]”hŒ	hold time”…””}”(hj“  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KKhj  ubjh  )”}”(hhh]”jM  )”}”(hhh]”(jR  )”}”(hŒ1min
- shortest (non-0) time we ever held the lock”h]”(jX  )”}”(hŒmin”h]”hŒmin”…””}”(hj«  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KDhj§  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ+shortest (non-0) time we ever held the lock”h]”hÉ)”}”(hjÁ  h]”hŒ+shortest (non-0) time we ever held the lock”…””}”(hjÃ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KEhj¿  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj¼  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h KEhj¹  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj§  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KDhj¤  ubjR  )”}”(hŒ(max
- longest time we ever held the lock”h]”(jX  )”}”(hŒmax”h]”hŒmax”…””}”(hjì  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KFhjè  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ"longest time we ever held the lock”h]”hÉ)”}”(hj  h]”hŒ"longest time we ever held the lock”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KGhj   ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjý  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h KGhjú  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjè  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KFhj¤  ubjR  )”}”(hŒ%total
- total time this lock was held”h]”(jX  )”}”(hŒtotal”h]”hŒtotal”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KHhj)  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒtotal time this lock was held”h]”hÉ)”}”(hjC  h]”hŒtotal time this lock was held”…””}”(hjE  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KIhjA  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj>  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h KIhj;  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj)  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KHhj¤  ubjR  )”}”(hŒ&avg
- average time this lock was held
”h]”(jX  )”}”(hŒavg”h]”hŒavg”…””}”(hjn  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jW  hŸh¶h KKhjj  ubjh  )”}”(hhh]”jm  )”}”(hhh]”jr  )”}”(hŒ average time this lock was held
”h]”hÉ)”}”(hŒaverage time this lock was held”h]”hŒaverage time this lock was held”…””}”(hj†  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KKhj‚  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj  ubah}”(h]”h ]”h"]”h$]”h&]”j  j‘  uh1jl  hŸh¶h KKhj|  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hjj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KKhj¤  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jL  hj¡  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jQ  hŸh¶h KKhjN  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jL  hjH  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jF  hŸh¶h K2hj  hžhubhÉ)”}”(hŒRThese numbers are gathered per lock class, per read/write state (when
applicable).”h]”hŒRThese numbers are gathered per lock class, per read/write state (when
applicable).”…””}”(hjÊ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KMhj  hžhubhÉ)”}”(hŒuIt also tracks 4 contention points per class. A contention point is a call site
that had to wait on lock acquisition.”h]”hŒuIt also tracks 4 contention points per class. A contention point is a call site
that had to wait on lock acquisition.”…””}”(hjØ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KPhj  hžhubh¢)”}”(hhh]”(h§)”}”(hŒConfiguration”h]”hŒConfiguration”…””}”(hjé  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjæ  hžhhŸh¶h KTubhÉ)”}”(hŒ1Lock statistics are enabled via CONFIG_LOCK_STAT.”h]”hŒ1Lock statistics are enabled via CONFIG_LOCK_STAT.”…””}”(hj÷  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KVhjæ  hžhubeh}”(h]”Œconfiguration”ah ]”h"]”Œconfiguration”ah$]”h&]”uh1h¡hj  hžhhŸh¶h KTubh¢)”}”(hhh]”(h§)”}”(hŒUsage”h]”hŒUsage”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h KYubhÉ)”}”(hŒ!Enable collection of statistics::”h]”hŒ Enable collection of statistics:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K[hj  hžhubj'  )”}”(hŒ$# echo 1 >/proc/sys/kernel/lock_stat”h]”hŒ$# echo 1 >/proc/sys/kernel/lock_stat”…””}”hj,  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h K]hj  hžhubhÉ)”}”(hŒ"Disable collection of statistics::”h]”hŒ!Disable collection of statistics:”…””}”(hj:  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K_hj  hžhubj'  )”}”(hŒ$# echo 0 >/proc/sys/kernel/lock_stat”h]”hŒ$# echo 0 >/proc/sys/kernel/lock_stat”…””}”hjH  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h Kahj  hžhubhÉ)”}”(hŒ%Look at the current lock statistics::”h]”hŒ$Look at the current lock statistics:”…””}”(hjV  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kchj  hžhubj'  )”}”(hX}  ( line numbers not part of actual output, done for clarity in the explanation
  below )

# less /proc/lock_stat

01 lock_stat version 0.4
02-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
03                              class name    con-bounces    contentions   waittime-min   waittime-max waittime-total   waittime-avg    acq-bounces   acquisitions   holdtime-min   holdtime-max holdtime-total   holdtime-avg
04-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
06                         &mm->mmap_sem-W:            46             84           0.26         939.10       16371.53         194.90          47291        2922365           0.16     2220301.69 17464026916.32        5975.99
07                         &mm->mmap_sem-R:            37            100           1.31      299502.61      325629.52        3256.30         212344       34316685           0.10        7744.91    95016910.20           2.77
08                         ---------------
09                           &mm->mmap_sem              1          [<ffffffff811502a7>] khugepaged_scan_mm_slot+0x57/0x280
10                           &mm->mmap_sem             96          [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
11                           &mm->mmap_sem             34          [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
12                           &mm->mmap_sem             17          [<ffffffff81127e71>] vm_munmap+0x41/0x80
13                         ---------------
14                           &mm->mmap_sem              1          [<ffffffff81046fda>] dup_mmap+0x2a/0x3f0
15                           &mm->mmap_sem             60          [<ffffffff81129e29>] SyS_mprotect+0xe9/0x250
16                           &mm->mmap_sem             41          [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
17                           &mm->mmap_sem             68          [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
18
19.............................................................................................................................................................................................................................
20
21                         unix_table_lock:           110            112           0.21          49.24         163.91           1.46          21094          66312           0.12         624.42       31589.81           0.48
22                         ---------------
23                         unix_table_lock             45          [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
24                         unix_table_lock             47          [<ffffffff8150b111>] unix_release_sock+0x31/0x250
25                         unix_table_lock             15          [<ffffffff8150ca37>] unix_find_other+0x117/0x230
26                         unix_table_lock              5          [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0
27                         ---------------
28                         unix_table_lock             39          [<ffffffff8150b111>] unix_release_sock+0x31/0x250
29                         unix_table_lock             49          [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
30                         unix_table_lock             20          [<ffffffff8150ca37>] unix_find_other+0x117/0x230
31                         unix_table_lock              4          [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0”h]”hX}  ( line numbers not part of actual output, done for clarity in the explanation
  below )

# less /proc/lock_stat

01 lock_stat version 0.4
02-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
03                              class name    con-bounces    contentions   waittime-min   waittime-max waittime-total   waittime-avg    acq-bounces   acquisitions   holdtime-min   holdtime-max holdtime-total   holdtime-avg
04-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
06                         &mm->mmap_sem-W:            46             84           0.26         939.10       16371.53         194.90          47291        2922365           0.16     2220301.69 17464026916.32        5975.99
07                         &mm->mmap_sem-R:            37            100           1.31      299502.61      325629.52        3256.30         212344       34316685           0.10        7744.91    95016910.20           2.77
08                         ---------------
09                           &mm->mmap_sem              1          [<ffffffff811502a7>] khugepaged_scan_mm_slot+0x57/0x280
10                           &mm->mmap_sem             96          [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
11                           &mm->mmap_sem             34          [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
12                           &mm->mmap_sem             17          [<ffffffff81127e71>] vm_munmap+0x41/0x80
13                         ---------------
14                           &mm->mmap_sem              1          [<ffffffff81046fda>] dup_mmap+0x2a/0x3f0
15                           &mm->mmap_sem             60          [<ffffffff81129e29>] SyS_mprotect+0xe9/0x250
16                           &mm->mmap_sem             41          [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
17                           &mm->mmap_sem             68          [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
18
19.............................................................................................................................................................................................................................
20
21                         unix_table_lock:           110            112           0.21          49.24         163.91           1.46          21094          66312           0.12         624.42       31589.81           0.48
22                         ---------------
23                         unix_table_lock             45          [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
24                         unix_table_lock             47          [<ffffffff8150b111>] unix_release_sock+0x31/0x250
25                         unix_table_lock             15          [<ffffffff8150ca37>] unix_find_other+0x117/0x230
26                         unix_table_lock              5          [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0
27                         ---------------
28                         unix_table_lock             39          [<ffffffff8150b111>] unix_release_sock+0x31/0x250
29                         unix_table_lock             49          [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
30                         unix_table_lock             20          [<ffffffff8150ca37>] unix_find_other+0x117/0x230
31                         unix_table_lock              4          [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0”…””}”hjd  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h Kehj  hžhubhÉ)”}”(hXr  This excerpt shows the first two lock class statistics. Line 01 shows the
output version - each time the format changes this will be updated. Line 02-04
show the header with column descriptions. Lines 05-18 and 20-31 show the actual
statistics. These statistics come in two parts; the actual stats separated by a
short separator (line 08, 13) from the contention points.”h]”hXr  This excerpt shows the first two lock class statistics. Line 01 shows the
output version - each time the format changes this will be updated. Line 02-04
show the header with column descriptions. Lines 05-18 and 20-31 show the actual
statistics. These statistics come in two parts; the actual stats separated by a
short separator (line 08, 13) from the contention points.”…””}”(hjr  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K‹hj  hžhubhÉ)”}”(hŒøLines 09-12 show the first 4 recorded contention points (the code
which tries to get the lock) and lines 14-17 show the first 4 recorded
contended points (the lock holder). It is possible that the max
con-bounces point is missing in the statistics.”h]”hŒøLines 09-12 show the first 4 recorded contention points (the code
which tries to get the lock) and lines 14-17 show the first 4 recorded
contended points (the lock holder). It is possible that the max
con-bounces point is missing in the statistics.”…””}”(hj€  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K‘hj  hžhubhÉ)”}”(hX  The first lock (05-18) is a read/write lock, and shows two lines above the
short separator. The contention points don't match the column descriptors,
they have two: contentions and [<IP>] symbol. The second set of contention
points are the points we're contending with.”h]”hX  The first lock (05-18) is a read/write lock, and shows two lines above the
short separator. The contention points donâ€™t match the column descriptors,
they have two: contentions and [<IP>] symbol. The second set of contention
points are the points weâ€™re contending with.”…””}”(hjŽ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K–hj  hžhubhÉ)”}”(hŒ-The integer part of the time values is in us.”h]”hŒ-The integer part of the time values is in us.”…””}”(hjœ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K›hj  hžhubhÉ)”}”(hŒ2Dealing with nested locks, subclasses may appear::”h]”hŒ1Dealing with nested locks, subclasses may appear:”…””}”(hjª  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khj  hžhubj'  )”}”(hXÏ	  32...........................................................................................................................................................................................................................
33
34                               &rq->lock:       13128          13128           0.43         190.53      103881.26           7.91          97454        3453404           0.00         401.11    13224683.11           3.82
35                               ---------
36                               &rq->lock          645          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
37                               &rq->lock          297          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
38                               &rq->lock          360          [<ffffffff8103c4c5>] select_task_rq_fair+0x1f0/0x74a
39                               &rq->lock          428          [<ffffffff81045f98>] scheduler_tick+0x46/0x1fb
40                               ---------
41                               &rq->lock           77          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
42                               &rq->lock          174          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
43                               &rq->lock         4715          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
44                               &rq->lock          893          [<ffffffff81340524>] schedule+0x157/0x7b8
45
46...........................................................................................................................................................................................................................
47
48                             &rq->lock/1:        1526          11488           0.33         388.73      136294.31          11.86          21461          38404           0.00          37.93      109388.53           2.84
49                             -----------
50                             &rq->lock/1        11526          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
51                             -----------
52                             &rq->lock/1         5645          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
53                             &rq->lock/1         1224          [<ffffffff81340524>] schedule+0x157/0x7b8
54                             &rq->lock/1         4336          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
55                             &rq->lock/1          181          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a”h]”hXÏ	  32...........................................................................................................................................................................................................................
33
34                               &rq->lock:       13128          13128           0.43         190.53      103881.26           7.91          97454        3453404           0.00         401.11    13224683.11           3.82
35                               ---------
36                               &rq->lock          645          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
37                               &rq->lock          297          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
38                               &rq->lock          360          [<ffffffff8103c4c5>] select_task_rq_fair+0x1f0/0x74a
39                               &rq->lock          428          [<ffffffff81045f98>] scheduler_tick+0x46/0x1fb
40                               ---------
41                               &rq->lock           77          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
42                               &rq->lock          174          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
43                               &rq->lock         4715          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
44                               &rq->lock          893          [<ffffffff81340524>] schedule+0x157/0x7b8
45
46...........................................................................................................................................................................................................................
47
48                             &rq->lock/1:        1526          11488           0.33         388.73      136294.31          11.86          21461          38404           0.00          37.93      109388.53           2.84
49                             -----------
50                             &rq->lock/1        11526          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
51                             -----------
52                             &rq->lock/1         5645          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
53                             &rq->lock/1         1224          [<ffffffff81340524>] schedule+0x157/0x7b8
54                             &rq->lock/1         4336          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
55                             &rq->lock/1          181          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a”…””}”hj¸  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h KŸhj  hžhubhÉ)”}”(hŒÌLine 48 shows statistics for the second subclass (/1) of &rq->lock class
(subclass starts from 0), since in this case, as line 50 suggests,
double_rq_lock actually acquires a nested lock of two spinlocks.”h]”hŒÌLine 48 shows statistics for the second subclass (/1) of &rq->lock class
(subclass starts from 0), since in this case, as line 50 suggests,
double_rq_lock actually acquires a nested lock of two spinlocks.”…””}”(hjÆ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¸hj  hžhubhÉ)”}”(hŒView the top contending locks::”h]”hŒView the top contending locks:”…””}”(hjÔ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¼hj  hžhubj'  )”}”(hX­  # grep : /proc/lock_stat | head
                      clockevents_lock:       2926159        2947636           0.15       46882.81  1784540466.34         605.41        3381345        3879161           0.00        2260.97    53178395.68          13.71
                   tick_broadcast_lock:        346460         346717           0.18        2257.43    39364622.71         113.54        3642919        4242696           0.00        2263.79    49173646.60          11.59
                &mapping->i_mmap_mutex:        203896         203899           3.36      645530.05 31767507988.39      155800.21        3361776        8893984           0.17        2254.15    14110121.02           1.59
                             &rq->lock:        135014         136909           0.18         606.09      842160.68           6.15        1540728       10436146           0.00         728.72    17606683.41           1.69
             &(&zone->lru_lock)->rlock:         93000          94934           0.16          59.18      188253.78           1.98        1199912        3809894           0.15         391.40     3559518.81           0.93
                       tasklist_lock-W:         40667          41130           0.23        1189.42      428980.51          10.43         270278         510106           0.16         653.51     3939674.91           7.72
                       tasklist_lock-R:         21298          21305           0.20        1310.05      215511.12          10.12         186204         241258           0.14        1162.33     1179779.23           4.89
                            rcu_node_1:         47656          49022           0.16         635.41      193616.41           3.95         844888        1865423           0.00         764.26     1656226.96           0.89
     &(&dentry->d_lockref.lock)->rlock:         39791          40179           0.15        1302.08       88851.96           2.21        2790851       12527025           0.10        1910.75     3379714.27           0.27
                            rcu_node_0:         29203          30064           0.16         786.55     1555573.00          51.74          88963         244254           0.00         398.87      428872.51           1.76”h]”hX­  # grep : /proc/lock_stat | head
                      clockevents_lock:       2926159        2947636           0.15       46882.81  1784540466.34         605.41        3381345        3879161           0.00        2260.97    53178395.68          13.71
                   tick_broadcast_lock:        346460         346717           0.18        2257.43    39364622.71         113.54        3642919        4242696           0.00        2263.79    49173646.60          11.59
                &mapping->i_mmap_mutex:        203896         203899           3.36      645530.05 31767507988.39      155800.21        3361776        8893984           0.17        2254.15    14110121.02           1.59
                             &rq->lock:        135014         136909           0.18         606.09      842160.68           6.15        1540728       10436146           0.00         728.72    17606683.41           1.69
             &(&zone->lru_lock)->rlock:         93000          94934           0.16          59.18      188253.78           1.98        1199912        3809894           0.15         391.40     3559518.81           0.93
                       tasklist_lock-W:         40667          41130           0.23        1189.42      428980.51          10.43         270278         510106           0.16         653.51     3939674.91           7.72
                       tasklist_lock-R:         21298          21305           0.20        1310.05      215511.12          10.12         186204         241258           0.14        1162.33     1179779.23           4.89
                            rcu_node_1:         47656          49022           0.16         635.41      193616.41           3.95         844888        1865423           0.00         764.26     1656226.96           0.89
     &(&dentry->d_lockref.lock)->rlock:         39791          40179           0.15        1302.08       88851.96           2.21        2790851       12527025           0.10        1910.75     3379714.27           0.27
                            rcu_node_0:         29203          30064           0.16         786.55     1555573.00          51.74          88963         244254           0.00         398.87      428872.51           1.76”…””}”hjâ  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h K¾hj  hžhubhÉ)”}”(hŒClear the statistics::”h]”hŒClear the statistics:”…””}”(hjð  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KÊhj  hžhubj'  )”}”(hŒ# echo 0 > /proc/lock_stat”h]”hŒ# echo 0 > /proc/lock_stat”…””}”hjþ  sbah}”(h]”h ]”h"]”h$]”h&]”j6  j7  uh1j&  hŸh¶h KÌhj  hžhubeh}”(h]”Œusage”ah ]”h"]”Œusage”ah$]”h&]”uh1h¡hj  hžhhŸh¶h KYubeh}”(h]”Œhow”ah ]”h"]”Œhow”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubeh}”(h]”Œlock-statistics”ah ]”h"]”Œlock statistics”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
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