On 25-09-09 14:09, Michael Tokarev wrote: > On 08.09.2025 19:12, Jakub Ružička wrote: > > #> time apt install texlive-latex-extra > > > > ... > > Building format(s) --all. > > This may take some time... done. > > > > real 165m27.254s > > user 164m32.000s > > sys 0m9.948s > > Which qemu version do you use for this test? > > I bet it is not the one in trixie.
Yeah, this was Bookworm qemu. > We had stronger default pauth implementation in qemu before, > which had a similar impact. The default one in qemu in trixie > should be much faster - there, the impact should be what I'm > seeing (about 2x the difference). With older qemu with stronger > pauth impl by default, 10x the difference is also expected. Indeed. Bookwrom qemu is 17x slower without pauth. Trixie qemu is 1.8x slower without pauth. > Please try with trixie's qemu-user (you can install qemu-user > package form trixie on an older system since this package is > self-contained). > > Now, please disable pauth entirely *in the guest* (in the chroot). > For this, the simplest way is to export QEMU_CPU=max,pauth=off so > that all processes running within your chroot inherits it. I can't > say how to do this in pbuilder though. For a manual test like the > above, you can set this variable when running apt command: > > # export QEMU_CPU=max,pauth=off > # time apt install ... Yes, this solves the issue - thanks a lot! I added `export QEMU_CPU=max,pauth=off` to /etc/pbuilderrc and all is good. Here is some profiling I did: # Bookwrom host ## Bookworm amd64 host, Trixie arm64 guest, pbuilder real 161m48.372s user 161m55.334s sys 0m10.065s ## Bookworm amd64 host, Trixie arm64 guest, pbuilder, pauth=off real 9m30.279s user 9m27.736s sys 0m7.939s ## Bookworm amd64 host, Trixie amd64 guest, pbuilder, pauth=off real 9m41.852s user 9m39.726s sys 0m8.273s # Trixie host (different machine) ## Trixie amd64 host, Trixie arm64 guest, pbuilder real 13m11.621s user 13m11.133s sys 0m10.129s ## Trixie amd64 host, Trixie arm64 guest, pbuilder, pauth=off real 7m26.362s user 7m31.176s sys 0m10.067s ## Trixie amd64 host, Trixie amd64 guest, pbuilder, pauth=off real 1m23.823s user 1m12.249s sys 0m5.424s ## Trixie amd64 host - direct apt install real 1m1.899s user 0m44.194s sys 0m6.593s Cheers, Jakub
