From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id C227D1FF164 for ; Fri, 8 Nov 2024 16:18:49 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id AC737115F8; Fri, 8 Nov 2024 16:18:49 +0100 (CET) Message-ID: Date: Fri, 8 Nov 2024 16:18:16 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Fiona Ebner To: pve-devel@lists.proxmox.com References: <20241030095240.11452-1-f.ebner@proxmox.com> Content-Language: en-US In-Reply-To: <20241030095240.11452-1-f.ebner@proxmox.com> X-SPAM-LEVEL: Spam detection results: 0 AWL -0.056 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_RPBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_SAFE_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [proxmox.com] Subject: Re: [pve-devel] [PATCH qemu] async snapshot: stop vCPU throttling after finishing 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: , Reply-To: Proxmox VE development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" Ping, as there are still new affected users showing up in the forum thread. Am 30.10.24 um 10:52 schrieb Fiona Ebner: > In the community forum, users reported issues about RCU stalls and > sluggish VMs after taking a snapshot with RAM in Proxmox VE [0]. Mario > was also experiencing similar issues from time to time and recently, > obtained a GDB stacktrace. The stacktrace showed that, in his case, > the vCPU threads were waiting in cpu_throttle_thread(). It is a good > guess that the issues in the forum could also be because of that. > > From searching in the source code, it seems that migration is the only > user of the vCPU throttling functions in QEMU relevant for Proxmox VE > (the only other place where it is used is the Cocoa UI). In > particular, RAM migration will begin throttling vCPUs for > auto-converge. > > In migration_iteration_finish() there is an unconditional call to > cpu_throttle_stop(), so do the same in the async snapshot code > specific to Proxmox VE. > > It's not clear why the issue began to surface more prominently only > now, since the vCPU throttling was there since commit 070afca258 > ("migration: Dynamic cpu throttling for auto-converge") in QEMU > v2.10.0. However, there were a lot of changes in the migration code > between v8.1.5 and v9.0.2 and a few of them might have affected the > likelihood of cpu_throttle_set() being called, for example, 4e1871c450 > ("migration: Don't serialize devices in qemu_savevm_state_iterate()") > > [0]: https://forum.proxmox.com/threads/153483 > > Reported-by: Mario Loderer > Signed-off-by: Fiona Ebner > Tested-by: Mario Loderer _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel