Bug#1117500: APT package installation is noticeably slower compared to previous versions (Debian 13)

Control: reassign -1 dpkg

On Mon, Oct 06, 2025 at 09:54:12PM +0300, bayram karahan wrote:
> Package: apt
> Version: 3.0.0~alpha3
> Severity: normal
> Tags: trixie performance
> 
> Subject: APT package installation is noticeably slower compared to previous
> versions (Debian 13)
> 
> Hello Debian team,
> 
> On Debian 13 (Trixie, Testing) with the new APT package manager (3.x
> series), package installation performance has significantly regressed
> compared to previous versions.
> 
> Installing a simple package used to take around 20–30 seconds with older
> APT releases (e.g., 2.6.x in Debian 12), but now the same operation often
> takes 2–3 minutes. This slowdown is especially noticeable on slower disks
> or network-based installs.

What is a simple package?

> 
> Observed behavior:
> - The “Downloading” phase runs at normal speed.
> - The “Configuring packages” or “Setting up” phases take much longer.

These steps are inside of dpkg, so I reassign accordingly.

I do not think there is anything actionable here, and it's likely a
problem with your system.

> - CPU usage remains low (around 5–10%).
> - Disk I/O is minimal.
> - It seems APT or dpkg triggers are spending excessive time in internal
> processing.

Perhaps your disk is failing? If it's not blocked on CPU then it will be
blocked on I/O, but not necessarily writes but ordering of syncs - you
will not see them associated as writes with the process, I'm not sure
if you see those at all as I/O in monitoring.

It's plausible dpkg added some extra fsync calls this cycle, but I
can't say for sure.
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