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hypervisor, vmm: Remove shared ownership of VmmOps

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This interface is used by the vCPU thread to delegate responsibility for
handling MMIO/PIO operations and to support different approaches than a
VM exit.

During profiling I found that we were spending 13.75% of the boot CPU
uage acquiring access to the object holding the VmmOps via
ArcSwap::load_full()

    13.75%     6.02%  vcpu0            cloud-hypervisor    [.] arc_swap::ArcSwapAny<T,S>::load_full
            |
            ---arc_swap::ArcSwapAny<T,S>::load_full
               |
                --13.43%--<hypervisor::kvm::KvmVcpu as hypervisor::cpu::Vcpu>::run
                          std::sys_common::backtrace::__rust_begin_short_backtrace
                          core::ops::function::FnOnce::call_once{{vtable-shim}}
                          std::sys::unix::thread::Thread::new::thread_start

However since the object implementing VmmOps does not need to be mutable
and it is only used from the vCPU side we can change the ownership to
being a simple Arc<> that is passed in when calling create_vcpu().

This completely removes the above CPU usage from subsequent profiles.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This commit is contained in:
Rob Bradford
2020-11-18 16:37:52 +00:00
committed by Samuel Ortiz
parent 6a591ca81d
commit 0fec326582
5 changed files with 46 additions and 48 deletions
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8
vmm/src/interrupt.rs
View File

@@ -415,7 +415,7 @@ mod tests {
fn test_get_set_dist_regs() {
let hv = hypervisor::new().unwrap();
let vm = hv.create_vm().unwrap();
let _ = vm.create_vcpu(0).unwrap();
let _ = vm.create_vcpu(0, None).unwrap();
let gic = create_gic(&vm, 1).expect("Cannot create gic");
let res = get_dist_regs(gic.device());
@@ -431,7 +431,7 @@ mod tests {
fn test_get_set_redist_regs() {
let hv = hypervisor::new().unwrap();
let vm = hv.create_vm().unwrap();
let _ = vm.create_vcpu(0).unwrap();
let _ = vm.create_vcpu(0, None).unwrap();
let gic = create_gic(&vm, 1).expect("Cannot create gic");
let mut gicr_typer = Vec::new();
@@ -449,7 +449,7 @@ mod tests {
fn test_get_set_icc_regs() {
let hv = hypervisor::new().unwrap();
let vm = hv.create_vm().unwrap();
let _ = vm.create_vcpu(0).unwrap();
let _ = vm.create_vcpu(0, None).unwrap();
let gic = create_gic(&vm, 1).expect("Cannot create gic");
let mut gicr_typer = Vec::new();
@@ -467,7 +467,7 @@ mod tests {
fn test_save_pending_tables() {
let hv = hypervisor::new().unwrap();
let vm = hv.create_vm().unwrap();
let _ = vm.create_vcpu(0).unwrap();
let _ = vm.create_vcpu(0, None).unwrap();
let gic = create_gic(&vm, 1).expect("Cannot create gic");
assert!(save_pending_tables(gic.device()).is_ok());