Hi, we had Delta in Ubuntu a long long time ago, but afaik there isn't any delta-need for years. To be clear, guest time as well as the guest visibility into steal time is very useful, but there shouldn't be any lack of it in Debian.
I had a try in (an old) debian 10.1 with 5.7.0-2-amd64 And there I can see the accounting moving just fine ubuntu@debian:~$ cat /proc/stat cpu 196 0 259 9243 60 0 1 23 0 0 cpu0 82 0 172 4579 39 0 1 10 0 0 qemu-system-x86_64 -nodefaults -nographic -accel kvm # wait a few seconds, and then abort it ubuntu@debian:~$ cat /proc/stat cpu 213 0 283 10926 73 0 4 32 7 0 cpu0 98 0 193 5397 52 0 3 15 7 0 cpu1 115 0 90 5528 20 0 0 16 0 0 The 7 seconds of boring some rom startup code is the accounting that you are looking for. Also as you can see in [1] there isn't any architecture note on this anymore (and I think there only was for steal time). So it really should work and does so in my experiment above. The original change is even in the history git pre 2.6.12 and the latter modifications are not new wither [2][3] I was updating and rebooting into 5.10.0-5-amd64 and I can confirm that it no longer works. (The same experiment as above) I've looked at the Ubuntu kernels for groovy [4] and hirsute [5], but found no related Delta on a quick check. IIRC the last upstream change [6] in that area was around v5.5 - so there should be no change. IMHO a kernel bug would be appropriate, @mjt I think you could even just re-target this one, there is no need to make it a different bug. @Thomas if instead you want to file a new bug, then look at [7] [1]: https://www.kernel.org/doc/html/latest/filesystems/proc.html#miscellaneous-kernel-statistics-in-proc-stat [2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce0e7b28 [3]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c574358e [4]: https://kernel.ubuntu.com/git/ubuntu/ubuntu-groovy.git/ [5]: https://kernel.ubuntu.com/git/ubuntu/ubuntu-hirsute.git/ [6]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5720821b [7]: https://wiki.debian.org/DebianKernelReportingBugs -- Christian Ehrhardt Staff Engineer, Ubuntu Server Canonical Ltd