Le mardi 31 décembre 2024, 18:32:09 UTC+1 Soren Stoutner a écrit : > On Tuesday, December 31, 2024 10:16:32 AM MST Michael Stone wrote: > > On Tue, Dec 31, 2024 at 05:31:36PM +0100, Sven Mueller wrote: > > >It feels wrong to me to justify such a heavy performance penalty this way > if > > > > Well, I guess we'd have to agree on the definition of "heavy performance > > penalty". I have not one debian system where dpkg install time is a > > bottleneck. > > So far, nobody has > produced any numbers showing that those penalties exist or how significant > they > are. As I don’t experience anything I could describe as a performance > problem > on any of my systems, I think the burden of proof is on those who are > experiencing those problems to demonstrate them concretely before we need to > spend effort trying to figure out what changes should be made to address them.
Here’s a quick « benchmark » in a sid Plasma desktop qemu VM where I had a snapshot of up-to-date sid from Nov 24th, upgrading to today’s sid : Summary: Upgrading: 658, Installing: 304, Removing: 58, Not Upgrading: 2 Download size: 0 B / 1 032 MB Space needed: 573 MB / 9 051 MB available # time apt -y full-upgrade real 9m49,143s user 2m16,581s sys 1m17,361s # time eatmydata apt -y full-upgrade real 3m25,268s user 2m26,820s sys 1m16,784s That’s close to a *3 times faster* wall clock time when run with eatmydata. The measurements are done after first running apt --download-only and taking the VM snapshot to avoid network impact. The VM installation is running plain ext4 with 4 vCPU / 4 GiB RAM. The host was otherwise idle. It runs sid on btrfs with default mount options on top of LUKS with the discard flag set. The VM’s qcow2 file is flagged with the C / No_COW xattr. It’s a recent Ryzen system with plenty of free RAM / disk space. While I don’t have a setup to quickly reproduce an upgrade on the bare metal host in my experience I see comparable impacts. And I’ve experienced similar behaviours on other machines. I won’t pretend I know what I’m doing, so I’m probably doing it wrong and my installs are probably broken in some obvious way. You were asking for data so here you go with a shiny data point. :) Happy new year, -- Aurélien
