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Diffstat (limited to 'Documentation/accounting/delay-accounting.rst')
| -rw-r--r-- | Documentation/accounting/delay-accounting.rst | 124 |
1 files changed, 104 insertions, 20 deletions
diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 7103b62ba6d7..86d7902a657f 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -16,6 +16,7 @@ d) memory reclaim e) thrashing f) direct compact g) write-protect copy +h) IRQ/SOFTIRQ and makes these statistics available to userspace through the taskstats interface. @@ -49,7 +50,7 @@ this structure. See 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 etc. +cache, direct compact, write-protect copy, IRQ/SOFTIRQ etc. Taking the difference of two successive readings of a given counter (say cpu_delay_total) for a task will give the delay @@ -99,27 +100,29 @@ Get delays, since system boot, for pid 10:: # ./getdelays -d -p 10 (output similar to next case) -Get sum of delays, since system boot, for all pids with tgid 5:: +Get sum and peak of delays, since system boot, for all pids with tgid 242:: - # ./getdelays -d -t 5 + bash-4.4# ./getdelays -d -t 242 print delayacct stats ON - TGID 5 - - - 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 - WPCOPY count delay total delay average - 0 0 0ms + 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 Get IO accounting for pid 1, it works only with -p:: @@ -128,3 +131,84 @@ Get IO accounting for pid 1, it works only with -p:: linuxrc: read=65536, write=0, cancelled_write=0 The above command can be used with -v to get more debug information. + +After the system starts, use `delaytop` to get the system-wide delay information, +which includes system-wide PSI information and Top-N high-latency tasks. +Note: PSI support requires `CONFIG_PSI=y` and `psi=1` for full functionality. + +`delaytop` is an interactive tool for monitoring system pressure and task delays. +It supports multiple sorting options, display modes, and real-time keyboard controls. + +Basic usage with default settings (sorts by CPU delay, shows top 20 tasks, refreshes every 2 seconds):: + + bash# ./delaytop + System Pressure Information: (avg10/avg60vg300/total) + CPU some: 0.0%/ 0.0%/ 0.0%/ 106137(ms) + CPU full: 0.0%/ 0.0%/ 0.0%/ 0(ms) + Memory full: 0.0%/ 0.0%/ 0.0%/ 0(ms) + Memory some: 0.0%/ 0.0%/ 0.0%/ 0(ms) + IO full: 0.0%/ 0.0%/ 0.0%/ 2240(ms) + IO some: 0.0%/ 0.0%/ 0.0%/ 2783(ms) + IRQ full: 0.0%/ 0.0%/ 0.0%/ 0(ms) + [o]sort [M]memverbose [q]quit + Top 20 processes (sorted by cpu delay): + PID TGID COMMAND CPU(ms) IO(ms) IRQ(ms) MEM(ms) + ------------------------------------------------------------------------ + 110 110 kworker/15:0H-s 27.91 0.00 0.00 0.00 + 57 57 cpuhp/7 3.18 0.00 0.00 0.00 + 99 99 cpuhp/14 2.97 0.00 0.00 0.00 + 51 51 cpuhp/6 0.90 0.00 0.00 0.00 + 44 44 kworker/4:0H-sy 0.80 0.00 0.00 0.00 + 60 60 ksoftirqd/7 0.74 0.00 0.00 0.00 + 76 76 idle_inject/10 0.31 0.00 0.00 0.00 + 100 100 idle_inject/14 0.30 0.00 0.00 0.00 + 1309 1309 systemsettings 0.29 0.00 0.00 0.00 + 45 45 cpuhp/5 0.22 0.00 0.00 0.00 + 63 63 cpuhp/8 0.20 0.00 0.00 0.00 + 87 87 cpuhp/12 0.18 0.00 0.00 0.00 + 93 93 cpuhp/13 0.17 0.00 0.00 0.00 + 1265 1265 acpid 0.17 0.00 0.00 0.00 + 1552 1552 sshd 0.17 0.00 0.00 0.00 + 2584 2584 sddm-helper 0.16 0.00 0.00 0.00 + 1284 1284 rtkit-daemon 0.15 0.00 0.00 0.00 + 1326 1326 nde-netfilter 0.14 0.00 0.00 0.00 + 27 27 cpuhp/2 0.13 0.00 0.00 0.00 + 631 631 kworker/11:2-rc 0.11 0.00 0.00 0.00 + +Interactive keyboard controls during runtime:: + + o - Select sort field (CPU, IO, IRQ, Memory, etc.) + M - Toggle display mode (Default/Memory Verbose) + q - Quit + +Available sort fields(use -s/--sort or interactive command):: + + cpu(c) - CPU delay + blkio(i) - I/O delay + irq(q) - IRQ delay + mem(m) - Total memory delay + swapin(s) - Swapin delay (memory verbose mode only) + freepages(r) - Freepages reclaim delay (memory verbose mode only) + thrashing(t) - Thrashing delay (memory verbose mode only) + compact(p) - Compaction delay (memory verbose mode only) + wpcopy(w) - Write page copy delay (memory verbose mode only) + +Advanced usage examples:: + + # ./delaytop -s blkio + Sorted by IO delay + + # ./delaytop -s mem -M + Sorted by memory delay in memory verbose mode + + # ./delaytop -p pid + Print delayacct stats + + # ./delaytop -P num + Display the top N tasks + + # ./delaytop -n num + Set delaytop refresh frequency (num times) + + # ./delaytop -d secs + Specify refresh interval as secs |