From: Wang Yaxin <wang.yaxin@xxxxxxxxxx> The "getdelays" can only display the latency of a single task by specifying a PID, we introduce the "delaytop" with the following capabilities: 1. system view: monitors latency metrics (CPU, I/O, memory, IRQ, etc.) for all system processes 2. supports field-based sorting (e.g., default sort by CPU latency in descending order) 3. dynamic interactive interface: focus on specific processes with --pid; limit displayed entries with --processes 20; control monitoring duration with --iterations; Signed-off-by: Fan Yu <fan.yu9@xxxxxxxxxx> Signed-off-by: Wang Yaxin <wang.yaxin@xxxxxxxxxx> Signed-off-by: Jiang Kun <jiang.kun2@xxxxxxxxxx> --- Documentation/accounting/delay-accounting.rst | 47 +++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 210c194d4a7b..664950328fb7 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -131,3 +131,50 @@ 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 Top-N high-latency tasks. +this tool supports sorting by CPU latency in descending order by default, +displays the top 20 high-latency tasks by default, and refreshes the latency +data every 2 seconds by default. + +Get Top-N tasks delay, since system boot:: + + bash# ./delaytop + Top 20 processes (sorted by CPU delay): + + PID TGID COMMAND CPU(ms) IO(ms) SWAP(ms) RCL(ms) THR(ms) CMP(ms) WP(ms) IRQ(ms) + --------------------------------------------------------------------------------------------- + 32 32 kworker/2:0H-sy 23.65 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 497 497 kworker/R-scsi_ 1.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 495 495 kworker/R-scsi_ 1.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 494 494 scsi_eh_0 1.12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 485 485 kworker/R-ata_s 0.90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 574 574 kworker/R-kdmfl 0.36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 34 34 idle_inject/3 0.33 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1123 1123 nde-netfilter 0.28 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 60 60 ksoftirqd/7 0.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 114 114 kworker/0:2-cgr 0.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 496 496 scsi_eh_1 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 51 51 cpuhp/6 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1667 1667 atd 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 45 45 cpuhp/5 0.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1102 1102 nde-backupservi 0.22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1098 1098 systemsettings 0.21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1100 1100 audit-monitor 0.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 53 53 migration/6 0.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 1482 1482 sshd 0.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + 39 39 cpuhp/4 0.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 + +Dynamic interactive interface of delaytop:: + + # ./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 -- 2.25.1
