Re: [PATCH 0/3] delaytop: add delay max, timestamp and sorting for top latency analysis

[Andrew Morton]

On Wed, 27 May 2026 21:55:24 +0800 (CST) <wang.yaxin@xxxxxxxxxx> wrote:

> From: Wang Yaxin <wang.yaxin@xxxxxxxxxx>
> 
> Previously delaytop only showed average delays. This patch adds:
> 
> 1. delay_max fields to track the maximum delay value for each delay type
>    (cpu, blkio, irq, swapin, freepages, thrashing, compact, wpcopy)
>    per task.
> 
> 2. The -t/--type option displays only the specified delay type with avg/max
>    values side by side, allowing focused analysis:
>      delaytop -t cpu    # Show only CPU delay with avg/max
>      delaytop -t wpcopy # Show Copy-on-Write delay with avg/max
> 
> 3. Wall-clock timestamp when each maximum delay occurred, displayed in the
>    MAX_TIMESTAMP column when using -t/--type option. This enables:
>    - Identifying the time when a process experienced an abnormal delay max
>    - Correlating delay max across multiple processes at the same timestamp
>    - Cross-referencing with logs, traces, or other metrics at that time
> 
> 4. When using -t/--type option, tasks are sorted by maximum delay value in
>    descending order (largest delay first), enabling quick identification of
>    top N processes with highest delay spikes.

Sounds useful.  Am I correct in assuming that you're a regular user of
delaytop and that these changes are based on your experience with it?

AI review claims to have found a number of things:
	https://sashiko.dev/#/patchset/20260527215524044fG7XSpgveHiaFhraq0yAi@xxxxxxxxxx