From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3F78C48BDF for ; Tue, 15 Jun 2021 05:25:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1B746140F for ; Tue, 15 Jun 2021 05:25:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229493AbhFOF1c (ORCPT ); Tue, 15 Jun 2021 01:27:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:55090 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbhFOF1c (ORCPT ); Tue, 15 Jun 2021 01:27:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EC7106140C; Tue, 15 Jun 2021 05:25:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623734728; bh=ccQSlvryxnxETl+l+tNcmXDaNhM9HlrwPO8EJMj+lco=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VqGj7By+d/l6mauCaIJU0c/KV3+rqklJy6aVtPt9CDzS7chlu0KCSgJohCt6ENRFB hZbqrm74sk+HbYGsLB2IFGR0HNlTtEDCiJ45q53lv3oXtKgbUi2LTn6IBkCySex0Ut v+lP6YYo+18NfLUwnU/avHN5VCfXxHGNOLiIYOEUwXTfMSpFZLeX2c5sZ6FUPzXloJ 3NKX84fPqnuujHvw9LaCnskPcKNSo1gTZ6gUirpGBA4TSmfzxMrFZtGX6C09vzgi+w E6/8CN+r511QtRKRmtzndwnz2BF4ZxWPZTO723jD82/gwROR8WDqwapMzkmkXos310 A6WpBeSUo/T1g== Date: Tue, 15 Jun 2021 08:25:24 +0300 From: Leon Romanovsky To: Jing Zhang Cc: KVM , KVMARM , LinuxMIPS , KVMPPC , LinuxS390 , Linuxkselftest , Paolo Bonzini , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Will Deacon , Huacai Chen , Aleksandar Markovic , Thomas Bogendoerfer , Paul Mackerras , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Peter Shier , Oliver Upton , David Rientjes , Emanuele Giuseppe Esposito , David Matlack , Ricardo Koller , Krish Sadhukhan , Fuad Tabba Subject: Re: [PATCH v9 0/5] KVM statistics data fd-based binary interface Message-ID: References: <20210614212155.1670777-1-jingzhangos@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210614212155.1670777-1-jingzhangos@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Mon, Jun 14, 2021 at 09:21:50PM +0000, Jing Zhang wrote: > This patchset provides a file descriptor for every VM and VCPU to read > KVM statistics data in binary format. > It is meant to provide a lightweight, flexible, scalable and efficient > lock-free solution for user space telemetry applications to pull the > statistics data periodically for large scale systems. The pulling > frequency could be as high as a few times per second. > In this patchset, every statistics data are treated to have some > attributes as below: > * architecture dependent or generic > * VM statistics data or VCPU statistics data > * type: cumulative, instantaneous, peak > * unit: none for simple counter, nanosecond, microsecond, > millisecond, second, Byte, KiByte, MiByte, GiByte. Clock Cycles > Since no lock/synchronization is used, the consistency between all > the statistics data is not guaranteed. That means not all statistics > data are read out at the exact same time, since the statistics date > are still being updated by KVM subsystems while they are read out. Sorry for my naive questions, but how does telemetry get statistics for hypervisors? Why is KVM different from hypervisors or NIC's statistics or any other high speed devices (RDMA) that generate tons of data? Thanks