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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
