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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id m6sm7999909wrw.9.2021.06.11.04.02.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Jun 2021 04:02:29 -0700 (PDT) Subject: Re: [PATCH v7 0/4] KVM statistics data fd-based binary interface To: Christian Borntraeger , Jing Zhang , KVM , KVMARM , LinuxMIPS , KVMPPC , LinuxS390 , Linuxkselftest , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Will Deacon , Huacai Chen , Aleksandar Markovic , Thomas Bogendoerfer , Paul Mackerras , 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 References: <20210603211426.790093-1-jingzhangos@google.com> <4b44c5a7-21c0-73c0-bb03-21806c83b4ae@de.ibm.com> From: Paolo Bonzini Message-ID: Date: Fri, 11 Jun 2021 13:02:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <4b44c5a7-21c0-73c0-bb03-21806c83b4ae@de.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 11/06/21 08:57, Christian Borntraeger wrote: > > On 03.06.21 23:14, 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 > > Are the debugfs things good enough, or do we want to also add the same > ioctl for the /dev/kvm to get the global counters as well, e.g. for > tools like kvm_stat? I think we should, yes. We should also add the summarized VCPU statistics to the VM-level file descriptor. However, it can be done in steps. Paolo