| From: Fan Yu <fan.yu9@zte.com.cn> |
| Subject: docs: update delaytop documentation for new interactive features |
| Date: Sun, 7 Sep 2025 00:14:57 +0800 (CST) |
| |
| This commit updates the delaytop documentation to reflect the newly |
| added features: |
| 1) Added comprehensive description of interactive keyboard controls |
| 2) Documented all available sort fields |
| 3) Added examples for advanced usage scenarios |
| 4) Included PSI availability note |
| |
| Link: https://lkml.kernel.org/r/20250907001457696qAqUGGkV1VfEO6OkVMovW@zte.com.cn |
| Signed-off-by: Fan Yu <fan.yu9@zte.com.cn> |
| Reviewed-by: xu xin <xu.xin16@zte.com.cn> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| Documentation/accounting/delay-accounting.rst | 89 ++++++++++------ |
| 1 file changed, 57 insertions(+), 32 deletions(-) |
| |
| --- a/Documentation/accounting/delay-accounting.rst~docs-update-delaytop-documentation-for-new-interactive-features |
| +++ a/Documentation/accounting/delay-accounting.rst |
| @@ -134,47 +134,72 @@ The above command can be used with -v to |
| |
| 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` 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. |
| +`delaytop` is an interactive tool for monitoring system pressure and task delays. |
| +It supports multiple sorting options, display modes, and real-time keyboard controls. |
| |
| -Get PSI information and Top-N tasks delay, since system boot:: |
| +Basic usage with default settings (sorts by CPU delay, shows top 20 tasks, refreshes every 2 seconds):: |
| |
| bash# ./delaytop |
| - System Pressure Information: (avg10/avg60/avg300/total) |
| - CPU some: 0.0%/ 0.0%/ 0.0%/ 345(ms) |
| + 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%/ 65(ms) |
| - IO some: 0.0%/ 0.0%/ 0.0%/ 79(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) |
| - 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) |
| - ---------------------------------------------------------------------------------------------- |
| - 161 161 zombie_memcg_re 1.40 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 130 130 blkcg_punt_bio 1.37 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 444 444 scsi_tmf_0 0.73 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1280 1280 rsyslogd 0.53 0.04 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 12 12 ksoftirqd/0 0.47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1277 1277 nbd-server 0.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 308 308 kworker/2:2-sys 0.41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 55 55 netns 0.36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1187 1187 acpid 0.31 0.03 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 6184 6184 kworker/1:2-sys 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 186 186 kaluad 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 18 18 ksoftirqd/1 0.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 185 185 kmpath_rdacd 0.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 190 190 kstrp 0.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 2759 2759 agetty 0.20 0.03 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1190 1190 kworker/0:3-sys 0.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1272 1272 sshd 0.15 0.04 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 1156 1156 license 0.15 0.11 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 134 134 md 0.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| - 6142 6142 kworker/3:2-xfs 0.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 |
| + [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) |
| |
| -Dynamic interactive interface of delaytop:: |
| +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 |
| _ |
