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authorLinus Torvalds <torvalds@linux-foundation.org>2022-01-20 10:41:01 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2022-01-20 10:41:01 +0200
commitf4484d138b31e8fa1ba410363b5b9664f68974af (patch)
tree6d776b1212604d3b16df499ae6e455e4a20544db /Documentation
parent1d1df41c5a33359a00e919d54eaebfb789711fdc (diff)
parentb1e78ef3be2533973953a35a56739fda7325875c (diff)
downloadlinux-f4484d138b31e8fa1ba410363b5b9664f68974af.tar.bz2
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: "55 patches. Subsystems affected by this patch series: percpu, procfs, sysctl, misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2, hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits) lib: remove redundant assignment to variable ret ubsan: remove CONFIG_UBSAN_OBJECT_SIZE kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB btrfs: use generic Kconfig option for 256kB page size limit arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB configs: introduce debug.config for CI-like setup delayacct: track delays from memory compact Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact delayacct: cleanup flags in struct task_delay_info and functions use it delayacct: fix incomplete disable operation when switch enable to disable delayacct: support swapin delay accounting for swapping without blkio panic: remove oops_id panic: use error_report_end tracepoint on warnings fs/adfs: remove unneeded variable make code cleaner FAT: use io_schedule_timeout() instead of congestion_wait() hfsplus: use struct_group_attr() for memcpy() region nilfs2: remove redundant pointer sbufs fs/binfmt_elf: use PT_LOAD p_align values for static PIE const_structs.checkpatch: add frequently used ops structs ...
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.