https://github.com/torvalds/linux
Revision d73eb57b80b98ae147e4e6a7d9877c2ba175f972 authored by Wanpeng Li on 18 July 2019, 11:39:06 UTC, committed by Paolo Bonzini on 20 July 2019, 07:00:45 UTC
Inspired by commit 9cac38dd5d (KVM/s390: Set preempted flag during vcpu wakeup and interrupt delivery), we want to also boost not just lock holders but also vCPUs that are delivering interrupts. Most smp_call_function_many calls are synchronous, so the IPI target vCPUs are also good yield candidates. This patch introduces vcpu->ready to boost vCPUs during wakeup and interrupt delivery time; unlike s390 we do not reuse vcpu->preempted so that voluntarily preempted vCPUs are taken into account by kvm_vcpu_on_spin, but vmx_vcpu_pi_put is not affected (VT-d PI handles voluntary preemption separately, in pi_pre_block). Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM: ebizzy -M vanilla boosting improved 1VM 21443 23520 9% 2VM 2800 8000 180% 3VM 1800 3100 72% Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs, one running ebizzy -M, the other running 'stress --cpu 2': w/ boosting + w/o pv sched yield(vanilla) vanilla boosting improved 1570 4000 155% w/ boosting + w/ pv sched yield(vanilla) vanilla boosting improved 1844 5157 179% w/o boosting, perf top in VM: 72.33% [kernel] [k] smp_call_function_many 4.22% [kernel] [k] call_function_i 3.71% [kernel] [k] async_page_fault w/ boosting, perf top in VM: 38.43% [kernel] [k] smp_call_function_many 6.31% [kernel] [k] async_page_fault 6.13% libc-2.23.so [.] __memcpy_avx_unaligned 4.88% [kernel] [k] call_function_interrupt Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 2417c87
Tip revision: d73eb57b80b98ae147e4e6a7d9877c2ba175f972 authored by Wanpeng Li on 18 July 2019, 11:39:06 UTC
KVM: Boost vCPUs that are delivering interrupts
KVM: Boost vCPUs that are delivering interrupts
Tip revision: d73eb57
File | Mode | Size |
---|---|---|
Makefile | -rw-r--r-- | 361 bytes |
compat.c | -rw-r--r-- | 2.2 KB |
ipc_sysctl.c | -rw-r--r-- | 6.1 KB |
mq_sysctl.c | -rw-r--r-- | 2.7 KB |
mqueue.c | -rw-r--r-- | 40.3 KB |
msg.c | -rw-r--r-- | 30.5 KB |
msgutil.c | -rw-r--r-- | 3.6 KB |
namespace.c | -rw-r--r-- | 4.6 KB |
sem.c | -rw-r--r-- | 62.1 KB |
shm.c | -rw-r--r-- | 43.0 KB |
syscall.c | -rw-r--r-- | 5.1 KB |
util.c | -rw-r--r-- | 22.8 KB |
util.h | -rw-r--r-- | 9.7 KB |
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