tools/delaytop: add flexible sorting by delay field
Patch series "tools/delaytop: implement real-time keyboard interaction
support", v2.
Current Limitations
===================
The current delaytop implementation has two main limitations:
1) Static sorting only by CPU delay Forcing users to restart with
different parameters to analyze other resource bottlenecks.
2) Memory delay information is always expanded Causing information
overload when only high-level memory pressure monitoring is needed.
Improvements
============
1) Implemented dynamic sorting capability
- Interactive key 'o' triggers sort mode.
- Supports sorting by CPU/IO/Memory/IRQ delays.
- Memory subcategories available in verbose mode.
* c - CPU delay (default)
* i - IO delay
* m - Total memory delay
* q - IRQ delay
* s/r/t/p/w - Memory subcategories (in verbose mode)
2) Added memory display modes
- Compact view (default): shows aggregated memory delays.
- Verbose view ('M' key): breaks down into memory sub-delays.
* SWAP - swapin delays
* RCL - freepages reclaim delays
* THR - thrashing delays
* CMP - compaction delays
* WP - write-protect copy delays
Practical benefits
==================
1) Dynamic Sorting for Real-Time Bottleneck Detection System
administrators can now dynamically change sorting to identify different
types of resource bottlenecks without restarting.
2) Enhanced Usability with On-Screen Keybindings More intuitive
interactive usage with on-screen keybindings help. Reduced screen
clutter when only memory overview is needed.
Use Case
========
# ./delaytop
System Pressure Information: (avg10/avg60vg300/total)
CPU some: 0.0%/ 0.0%/ 0.0%/ 106817(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%/ 2245(ms)
IO some: 0.0%/ 0.0%/ 0.0%/ 2791(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
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
60 60 ksoftirqd/7 0.28 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
# ./delaytop -M
System Pressure Information: (avg10/avg60vg300/total)
CPU some: 0.0%/ 0.0%/ 0.0%/ 106827(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%/ 2245(ms)
IO some: 0.0%/ 0.0%/ 0.0%/ 2791(ms)
IRQ full: 0.0%/ 0.0%/ 0.0%/ 0(ms)
[o]sort [M]memverbose [q]quit
Top 20 processes (sorted by mem delay):
PID TGID COMMAND MEM(ms) SWAP(ms) RCL(ms) THR(ms) CMP(ms) WP(ms)
------------------------------------------------------------------------------------------
121732 121732 delaytop 0.01 0.00 0.00 0.00 0.00 0.01
95876 95876 top 0.00 0.00 0.00 0.00 0.00 0.00
121641 121641 systemd-userwor 0.00 0.00 0.00 0.00 0.00 0.00
121693 121693 systemd-userwor 0.00 0.00 0.00 0.00 0.00 0.00
121661 121661 systemd-userwor 0.00 0.00 0.00 0.00 0.00 0.00
1 1 systemd 0.00 0.00 0.00 0.00 0.00 0.00
2 2 kthreadd 0.00 0.00 0.00 0.00 0.00 0.00
3 3 pool_workqueue_ 0.00 0.00 0.00 0.00 0.00 0.00
4 4 kworker/R-rcu_g 0.00 0.00 0.00 0.00 0.00 0.00
5 5 kworker/R-rcu_p 0.00 0.00 0.00 0.00 0.00 0.00
6 6 kworker/R-slub_ 0.00 0.00 0.00 0.00 0.00 0.00
7 7 kworker/R-netns 0.00 0.00 0.00 0.00 0.00 0.00
9 9 kworker/0:0H-sy 0.00 0.00 0.00 0.00 0.00 0.00
11 11 kworker/u32:0-n 0.00 0.00 0.00 0.00 0.00 0.00
12 12 kworker/R-mm_pe 0.00 0.00 0.00 0.00 0.00 0.00
13 13 rcu_tasks_kthre 0.00 0.00 0.00 0.00 0.00 0.00
14 14 rcu_tasks_rude_ 0.00 0.00 0.00 0.00 0.00 0.00
15 15 rcu_tasks_trace 0.00 0.00 0.00 0.00 0.00 0.00
16 16 ksoftirqd/0 0.00 0.00 0.00 0.00 0.00 0.00
17 17 rcu_preempt 0.00 0.00 0.00 0.00 0.00 0.00
When psi is not enabled:
# ./delaytop
System Pressure Information: (avg10/avg60vg300/total)
PSI not found: check if psi=1 enabled in cmdline
This patch (of 5):
The delaytop tool only supported sorting by CPU delay, which limited its
usefulness when users needed to identify bottlenecks in other subsystems.
Users had no way to sort processes by IO, IRQ, or other delay types to
quickly pinpoint specific performance issues.
Add -s/--sort option to allow sorting by different delay types. Users can
now quickly identify bottlenecks in specific subsystems by sorting
processes by the relevant delay metric.
Link: https://lkml.kernel.org/r/20250907001101305vrTGnXaRNvtmsGkp-Ljk_@zte.com.cn
Link: https://lkml.kernel.org/r/20250907001205573L3XpsQMIQnLgDqiiKYd3H@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / thirdparty / kernel / linux.git / commit
