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authorLeonardo Bras <leobras@redhat.com>2024-05-10 23:05:56 -0300
committerPaolo Bonzini <pbonzini@redhat.com>2024-09-04 10:44:42 -0400
commit593377036e50de89132bc1222800174fde0780ec (patch)
tree84cfe3462a8af2675378fe39427c479587cded1f /tools/perf/scripts/python/exported-sql-viewer.py
parentd30d9ee94cc0e7ae91da7251d9c280b8cf7e5e4d (diff)
kvm: Note an RCU quiescent state on guest exit
As of today, KVM notes a quiescent state only in guest entry, which is good as it avoids the guest being interrupted for current RCU operations. While the guest vcpu runs, it can be interrupted by a timer IRQ that will check for any RCU operations waiting for this CPU. In case there are any of such, it invokes rcu_core() in order to sched-out the current thread and note a quiescent state. This occasional schedule work will introduce tens of microsseconds of latency, which is really bad for vcpus running latency-sensitive applications, such as real-time workloads. So, note a quiescent state in guest exit, so the interrupted guests is able to deal with any pending RCU operations before being required to invoke rcu_core(), and thus avoid the overhead of related scheduler work. Signed-off-by: Leonardo Bras <leobras@redhat.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Sean Christopherson <seanjc@google.com> Message-ID: <20240511020557.1198200-1-leobras@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'tools/perf/scripts/python/exported-sql-viewer.py')
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