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authorwangyong2022-01-19 18:10:12 -0800
committerLinus Torvalds2022-01-20 08:52:55 +0200
commitec710aa8b2385e6a2239f79120fbf9b78400865b (patch)
treeaaf7b6521237a704b9e2c5000fb293aa89b29a3d /Documentation
parent1193829da1a6728249cd02577a020bd64fd9c160 (diff)
Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact
Add thrashing page cache and direct compact related descriptions and update the usage of getdelays userspace utility. The following patches modifications have been updated: https://lore.kernel.org/all/20190312102002.31737-4-jinpuwang@gmail.com/ https://lore.kernel.org/all/1638619795-71451-1-git-send-email- wang.yong12@zte.com.cn/ Link: https://lkml.kernel.org/r/1639583021-92977-1-git-send-email-wang.yong12@zte.com.cn Signed-off-by: wangyong <wang.yong12@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Reported-by: Zeal Robot <zealci@zte.com.cn> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/accounting/delay-accounting.rst55
1 files changed, 27 insertions, 28 deletions
diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst
index 1b8b46deeb29..197fe319cbec 100644
--- a/Documentation/accounting/delay-accounting.rst
+++ b/Documentation/accounting/delay-accounting.rst
@@ -13,6 +13,8 @@ a) waiting for a CPU (while being runnable)
b) completion of synchronous block I/O initiated by the task
c) swapping in pages
d) memory reclaim
+e) thrashing page cache
+f) direct compact
and makes these statistics available to userspace through
the taskstats interface.
@@ -41,11 +43,12 @@ generic data structure to userspace corresponding to per-pid and per-tgid
statistics. The delay accounting functionality populates specific fields of
this structure. See
- include/linux/taskstats.h
+ include/uapi/linux/taskstats.h
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 etc.
+delay seen for cpu, sync block I/O, swapin, memory reclaim, thrash page
+cache, direct compact etc.
Taking the difference of two successive readings of a given
counter (say cpu_delay_total) for a task will give the delay
@@ -88,41 +91,37 @@ seen.
General format of the getdelays command::
- getdelays [-t tgid] [-p pid] [-c cmd...]
-
+ getdelays [-dilv] [-t tgid] [-p pid]
Get delays, since system boot, for pid 10::
- # ./getdelays -p 10
+ # ./getdelays -d -p 10
(output similar to next case)
Get sum of delays, since system boot, for all pids with tgid 5::
- # ./getdelays -t 5
-
-
- CPU count real total virtual total delay total
- 7876 92005750 100000000 24001500
- IO count delay total
- 0 0
- SWAP count delay total
- 0 0
- RECLAIM count delay total
- 0 0
+ # ./getdelays -d -t 5
+ print delayacct stats ON
+ TGID 5
-Get delays seen in executing a given simple command::
- # ./getdelays -c ls /
+ CPU count real total virtual total delay total delay average
+ 8 7000000 6872122 3382277 0.423ms
+ IO count delay total delay average
+ 0 0 0ms
+ SWAP count delay total delay average
+ 0 0 0ms
+ RECLAIM count delay total delay average
+ 0 0 0ms
+ THRASHING count delay total delay average
+ 0 0 0ms
+ COMPACT count delay total delay average
+ 0 0 0ms
- bin data1 data3 data5 dev home media opt root srv sys usr
- boot data2 data4 data6 etc lib mnt proc sbin subdomain tmp var
+Get IO accounting for pid 1, it works only with -p::
+ # ./getdelays -i -p 1
+ printing IO accounting
+ linuxrc: read=65536, write=0, cancelled_write=0
- CPU count real total virtual total delay total
- 6 4000250 4000000 0
- IO count delay total
- 0 0
- SWAP count delay total
- 0 0
- RECLAIM count delay total
- 0 0
+The above command can be used with -v to get more debug information.