Messages in this thread | | | Subject | Re: [RFC PATCH 0/7] Add support for monitoring guest TLB operations | From | Paolo Bonzini <> | Date | Wed, 17 Aug 2016 19:02:32 +0200 |
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On 17/08/2016 19:01, Punit Agrawal wrote: >> Can you explain what this is used for? In other words, why would this >> be used instead of just running perf in the guest? > > As TLB maintenance operations are synchronised in hardware, they can > impact performance beyond the guest. The operations generate traffic on > the interconnect and depending on the implementation, they can also > affect the remote TLB's translation bandwidth. > > These patches are useful on systems where the host and guest are > controlled by different users - the guest could be running arbitrary > software. > > Having the ability to monitor the usage of guest TLB invalidations in > the host can be useful to diagnose performance issues on such systems.
Are there hardware performance counters for these operations?
Paolo
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