I recently upgraded from ubuntu 24.04 to 26.04 and thus from (I presume) opam 2.1 to 2.5. It appears that Emacs takes a very long time to start due to user-setup’s opam-detect-installed-tools, which does opam list --installed --short --safe --color=never to get the list of tools for which it can do…

I was going to write that I can’t reproduce, but testing this I discovered I hadn’t finished upgrading opam to 2.5.1 and then after upgrading I could reproduce: $ time opam list --installed --short --safe --color=never >/dev/null real 0m0.196s user 0m0.156s sys 0m0.040s $ opam --version 2.5.0 $ ti…

Does the situation improve if you do it once without the --safe ? I feel it got better for me after that but still slower than it used to be ``real 0m0,619s user 0m0,483s sys 0m0,134s ``

[image] reynir: 2.5.0 $ time opam list --installed --short --safe --color=never >/dev/null # after upgrading opam real 0m2.308s user 0m1.683s sys 0m0.401s Try using strace to pinpoint what is slow (e.g. a particular system call, too many system calls, etc.). This will print a summary of all…

@reynir @ysalmon i’m unable to reproduce this locally but you might have an easier time debugging using --debug or even --debug-level=3 (and removing --safe(?) otherwise it doesn’t show any debug output, that seems like a bug…). debug-levels above 0 show timed traces of internal opam actions (that …

In my case it spends a lot of time in compare_case calling the GC. This appears to be already fixed on master by Make OpamStd.String.compare_case allocation free · ocaml/opam@c4984a2 · GitHub hyperfine --warmup 1 '\_build/default/src/client/opamMain.exe list -- installed --short --color=never >/dev…

Hi! Sorry, I’ve been away from vacation. I no longer can reproduce. I have touched the computer very little in the meantime so I’m not sure what’s changed. $ time opam list --installed --short --safe --color=never >/dev/null real 0m0.236s user 0m0.184s sys 0m0.053s $ opam --version 2.5.1

[image] reynir: Hi! Sorry, I’ve been away from vacation. I no longer can reproduce. I have touched the computer very little in the meantime so I’m not sure what’s changed. Check the timestamp on ~/.opam/repo/state*.cache. If I delete the state cache then all opam list commands take 1.7s. Run…

Interesting! Yes, I had a state cache from yesterday 10:26 CEST. If I deleted the cache I get the 2 second delay which then disappears after running the command without --safe exactly as you describe.

Thanks, I’ve opened an issue here with some suggestions , in particular the opam shell integrations should probably detect and update stale caches (i.e. the equivalent of running opam list without --safe), which would avoid this problem on version upgrades. (There’d be a one-off cost to update the s…

Opam list very slow on opam 2.5

Ecosystem

ancolie June 2, 2026, 4:03pm 5

FYI, you can now directly do:

$ perf record --call-graph=dwarf -F 499 -- opam list --installed --short --color=never >/dev/null
$ perf script report flamegraph

Flamegraphs and recursive functions

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Opam list very slow on opam 2.5

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