€•[I      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/accounting/delay-accounting”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$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ//translations/zh_TW/accounting/delay-accounting”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ//translations/it_IT/accounting/delay-accounting”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ//translations/ja_JP/accounting/delay-accounting”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ//translations/ko_KR/accounting/delay-accounting”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ//translations/sp_SP/accounting/delay-accounting”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒDelay accounting”h]”hŒDelay accounting”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒI/var/lib/git/docbuild/linux/Documentation/accounting/delay-accounting.rst”h KubhŒ	paragraph”“”)”}”(hŒ—Tasks encounter delays in execution when they wait
for some kernel resource to become available e.g. a
runnable task may wait for a free CPU to run on.”h]”hŒ—Tasks encounter delays in execution when they wait
for some kernel resource to become available e.g. a
runnable task may wait for a free CPU to run on.”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒ[The per-task delay accounting functionality measures
the delays experienced by a task while”h]”hŒ[The per-task delay accounting functionality measures
the delays experienced by a task while”…””}”(hhÇhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K	hh£hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ(waiting for a CPU (while being runnable)”h]”h¸)”}”(hhÞh]”hŒ(waiting for a CPU (while being runnable)”…””}”(hhàhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÜubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒ9completion of synchronous block I/O initiated by the task”h]”h¸)”}”(hhõh]”hŒ9completion of synchronous block I/O initiated by the task”…””}”(hh÷hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhóubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒswapping in pages”h]”h¸)”}”(hj  h]”hŒswapping in pages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj
  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒmemory reclaim”h]”h¸)”}”(hj#  h]”hŒmemory reclaim”…””}”(hj%  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj!  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒ	thrashing”h]”h¸)”}”(hj:  h]”hŒ	thrashing”…””}”(hj<  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj8  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒdirect compact”h]”h¸)”}”(hjQ  h]”hŒdirect compact”…””}”(hjS  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjO  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒwrite-protect copy”h]”h¸)”}”(hjh  h]”hŒwrite-protect copy”…””}”(hjj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjf  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h NubhÛ)”}”(hŒIRQ/SOFTIRQ
”h]”h¸)”}”(hŒIRQ/SOFTIRQ”h]”hŒIRQ/SOFTIRQ”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj}  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÚhh×hžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œ
loweralpha”Œprefix”hŒsuffix”Œ)”uh1hÕhh£hžhhŸh¶h Kubh¸)”}”(hŒRand makes these statistics available to userspace through
the taskstats interface.”h]”hŒRand makes these statistics available to userspace through
the taskstats interface.”…””}”(hj   hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒÊSuch delays provide feedback for setting a task's cpu priority,
io priority and rss limit values appropriately. Long delays for
important tasks could be a trigger for raising its corresponding priority.”h]”hŒÌSuch delays provide feedback for setting a taskâ€™s cpu priority,
io priority and rss limit values appropriately. Long delays for
important tasks could be a trigger for raising its corresponding priority.”…””}”(hj®  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hX!  The functionality, through its use of the taskstats interface, also provides
delay statistics aggregated for all tasks (or threads) belonging to a
thread group (corresponding to a traditional Unix process). This is a commonly
needed aggregation that is more efficiently done by the kernel.”h]”hX!  The functionality, through its use of the taskstats interface, also provides
delay statistics aggregated for all tasks (or threads) belonging to a
thread group (corresponding to a traditional Unix process). This is a commonly
needed aggregation that is more efficiently done by the kernel.”…””}”(hj¼  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hX!  Userspace utilities, particularly resource management applications, can also
aggregate delay statistics into arbitrary groups. To enable this, delay
statistics of a task are available both during its lifetime as well as on its
exit, ensuring continuous and complete monitoring can be done.”h]”hX!  Userspace utilities, particularly resource management applications, can also
aggregate delay statistics into arbitrary groups. To enable this, delay
statistics of a task are available both during its lifetime as well as on its
exit, ensuring continuous and complete monitoring can be done.”…””}”(hjÊ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K!hh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒ	Interface”h]”hŒ	Interface”…””}”(hjÛ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjØ  hžhhŸh¶h K(ubh¸)”}”(hX2  Delay accounting uses the taskstats interface which is described
in detail in a separate document in this directory. Taskstats returns a
generic data structure to userspace corresponding to per-pid and per-tgid
statistics. The delay accounting functionality populates specific fields of
this structure. See”h]”hX2  Delay accounting uses the taskstats interface which is described
in detail in a separate document in this directory. Taskstats returns a
generic data structure to userspace corresponding to per-pid and per-tgid
statistics. The delay accounting functionality populates specific fields of
this structure. See”…””}”(hjé  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K*hjØ  hžhubhŒblock_quote”“”)”}”(hŒinclude/uapi/linux/taskstats.h
”h]”h¸)”}”(hŒinclude/uapi/linux/taskstats.h”h]”hŒinclude/uapi/linux/taskstats.h”…””}”(hjý  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K0hjù  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j÷  hŸh¶h K0hjØ  hžhubh¸)”}”(hX	  for a description of the fields pertaining to delay accounting.
It will generally be in the form of counters returning the cumulative
delay seen for cpu, sync block I/O, swapin, memory reclaim, thrash page
cache, direct compact, write-protect copy, IRQ/SOFTIRQ etc.”h]”hX	  for a description of the fields pertaining to delay accounting.
It will generally be in the form of counters returning the cumulative
delay seen for cpu, sync block I/O, swapin, memory reclaim, thrash page
cache, direct compact, write-protect copy, IRQ/SOFTIRQ etc.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K2hjØ  hžhubh¸)”}”(hŒÉTaking the difference of two successive readings of a given
counter (say cpu_delay_total) for a task will give the delay
experienced by the task waiting for the corresponding resource
in that interval.”h]”hŒÉTaking the difference of two successive readings of a given
counter (say cpu_delay_total) for a task will give the delay
experienced by the task waiting for the corresponding resource
in that interval.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K7hjØ  hžhubh¸)”}”(hX  When a task exits, records containing the per-task statistics
are sent to userspace without requiring a command. If it is the last exiting
task of a thread group, the per-tgid statistics are also sent. More details
are given in the taskstats interface description.”h]”hX  When a task exits, records containing the per-task statistics
are sent to userspace without requiring a command. If it is the last exiting
task of a thread group, the per-tgid statistics are also sent. More details
are given in the taskstats interface description.”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K<hjØ  hžhubh¸)”}”(hŒ×The getdelays.c userspace utility in tools/accounting directory allows simple
commands to be run and the corresponding delay statistics to be displayed. It
also serves as an example of using the taskstats interface.”h]”hŒ×The getdelays.c userspace utility in tools/accounting directory allows simple
commands to be run and the corresponding delay statistics to be displayed. It
also serves as an example of using the taskstats interface.”…””}”(hj;  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KAhjØ  hžhubeh}”(h]”Œ	interface”ah ]”h"]”Œ	interface”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K(ubh¢)”}”(hhh]”(h§)”}”(hŒUsage”h]”hŒUsage”…””}”(hjT  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjQ  hžhhŸh¶h KFubh¸)”}”(hŒCompile the kernel with::”h]”hŒCompile the kernel with:”…””}”(hjb  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KHhjQ  hžhubhŒliteral_block”“”)”}”(hŒ+CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASKSTATS=y”h]”hŒ+CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASKSTATS=y”…””}”hjr  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1jp  hŸh¶h KJhjQ  hžhubh¸)”}”(hŒDDelay accounting is disabled by default at boot up.
To enable, add::”h]”hŒCDelay accounting is disabled by default at boot up.
To enable, add:”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KMhjQ  hžhubjq  )”}”(hŒ	delayacct”h]”hŒ	delayacct”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”j€  j  uh1jp  hŸh¶h KPhjQ  hžhubh¸)”}”(hX  to the kernel boot options. The rest of the instructions below assume this has
been done. Alternatively, use sysctl kernel.task_delayacct to switch the state
at runtime. Note however that only tasks started after enabling it will have
delayacct information.”h]”hX  to the kernel boot options. The rest of the instructions below assume this has
been done. Alternatively, use sysctl kernel.task_delayacct to switch the state
at runtime. Note however that only tasks started after enabling it will have
delayacct information.”…””}”(hjž  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KRhjQ  hžhubh¸)”}”(hŒçAfter the system has booted up, use a utility
similar to  getdelays.c to access the delays
seen by a given task or a task group (tgid).
The utility also allows a given command to be
executed and the corresponding delays to be
seen.”h]”hŒçAfter the system has booted up, use a utility
similar to  getdelays.c to access the delays
seen by a given task or a task group (tgid).
The utility also allows a given command to be
executed and the corresponding delays to be
seen.”…””}”(hj¬  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KWhjQ  hžhubh¸)”}”(hŒ)General format of the getdelays command::”h]”hŒ(General format of the getdelays command:”…””}”(hjº  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K^hjQ  hžhubjq  )”}”(hŒ$getdelays [-dilv] [-t tgid] [-p pid]”h]”hŒ$getdelays [-dilv] [-t tgid] [-p pid]”…””}”hjÈ  sbah}”(h]”h ]”h"]”h$]”h&]”j€  j  uh1jp  hŸh¶h K`hjQ  hžhubh¸)”}”(hŒ+Get delays, since system boot, for pid 10::”h]”hŒ*Get delays, since system boot, for pid 10:”…””}”(hjÖ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KbhjQ  hžhubjq  )”}”(hŒ4# ./getdelays -d -p 10
(output similar to next case)”h]”hŒ4# ./getdelays -d -p 10
(output similar to next case)”…””}”hjä  sbah}”(h]”h ]”h"]”h$]”h&]”j€  j  uh1jp  hŸh¶h KdhjQ  hžhubh¸)”}”(hŒKGet sum and peak of delays, since system boot, for all pids with tgid 242::”h]”hŒJGet sum and peak of delays, since system boot, for all pids with tgid 242:”…””}”(hjò  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KghjQ  hžhubjq  )”}”(hXr  bash-4.4# ./getdelays -d -t 242
print delayacct stats ON
TGID    242


CPU         count     real total  virtual total    delay total  delay average      delay max      delay min
               39      156000000      156576579        2111069          0.054ms     0.212296ms     0.031307ms
IO          count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
SWAP        count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
RECLAIM     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
THRASHING   count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
COMPACT     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
WPCOPY      count    delay total  delay average      delay max      delay min
              156       11215873          0.072ms     0.207403ms     0.033913ms
IRQ         count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms”h]”hXr  bash-4.4# ./getdelays -d -t 242
print delayacct stats ON
TGID    242


CPU         count     real total  virtual total    delay total  delay average      delay max      delay min
               39      156000000      156576579        2111069          0.054ms     0.212296ms     0.031307ms
IO          count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
SWAP        count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
RECLAIM     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
THRASHING   count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
COMPACT     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
WPCOPY      count    delay total  delay average      delay max      delay min
              156       11215873          0.072ms     0.207403ms     0.033913ms
IRQ         count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms”…””}”hj   sbah}”(h]”h ]”h"]”h$]”h&]”j€  j  uh1jp  hŸh¶h KihjQ  hžhubh¸)”}”(hŒ4Get IO accounting for pid 1, it works only with -p::”h]”hŒ3Get IO accounting for pid 1, it works only with -p:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjQ  hžhubjq  )”}”(hŒ\# ./getdelays -i -p 1
printing IO accounting
linuxrc: read=65536, write=0, cancelled_write=0”h]”hŒ\# ./getdelays -i -p 1
printing IO accounting
linuxrc: read=65536, write=0, cancelled_write=0”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”j€  j  uh1jp  hŸh¶h KhjQ  hžhubh¸)”}”(hŒDThe above command can be used with -v to get more debug information.”h]”hŒDThe above command can be used with -v to get more debug information.”…””}”(hj*  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K…hjQ  hžhubeh}”(h]”Œusage”ah ]”h"]”Œusage”ah$]”h&]”uh1h¡hh£hžhhŸh¶h KFubeh}”(h]”Œdelay-accounting”ah ]”h"]”Œdelay accounting”ah$]”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
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
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