From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 6BCB170FA8 for ; Tue, 6 Apr 2021 20:49:07 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 57A20A02B for ; Tue, 6 Apr 2021 20:48:37 +0200 (CEST) Received: from mail.namespace.at (mail.namespace.at [IPv6:2a01:190:1801:100::235]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 70800A01F for ; Tue, 6 Apr 2021 20:48:35 +0200 (CEST) Date: Tue, 6 Apr 2021 20:48:28 +0200 From: Chris Hofstaedtler To: pve-devel@lists.proxmox.com Message-ID: <20210406184828.y23ajkfqgfazk4qk@zeha.at> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-SPAM-LEVEL: Spam detection results: 1 KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment KAM_LAZY_DOMAIN_SECURITY 1 Sending domain does not have any anti-forgery methods SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_NONE 0.001 SPF: sender does not publish an SPF Record Subject: [pve-devel] Fwd: Bug#986371: Indeed this should work (also adding trivial test-case) X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Apr 2021 18:49:07 -0000 Hi, I believe you'll find Debian bug #986371 of interest. In Kernels 5.10+ the "guest time" accounting appears to be broken, in both Debian and Ubuntu. See https://bugs.debian.org/986371 for further details. Best, Chris From: Christian Ehrhardt Subject: Bug#986371: Indeed this should work (also adding trivial test-case) 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