Re: [Xen-devel] [PATCH v6 00/11] implement vcpu preempted check

Konrad Rzeszutek Wilk
2016-10-28T19:38:17Z

On Fri, Oct 28, 2016 at 04:11:16AM -0400, Pan Xinhui wrote:
> change from v5:
> spilt x86/kvm patch into guest/host part.
> introduce kvm_write_guest_offset_cached.
> fix some typos.
> rebase patch onto 4.9.2
> change from v4:
> spilt x86 kvm vcpu preempted check into two patches.
> add documentation patch.
> add x86 vcpu preempted check patch under xen
> add s390 vcpu preempted check patch
> change from v3:
> add x86 vcpu preempted check patch
> change from v2:
> no code change, fix typos, update some comments
> change from v1:
> a simplier definition of default vcpu_is_preempted
> skip mahcine type check on ppc, and add config. remove dedicated macro.
> add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner.
> add more comments
> thanks boqun and Peter's suggestion.
>
> This patch set aims to fix lock holder preemption issues.

Do you have a git tree with these patches?

>
> test-case:
> perf record -a perf bench sched messaging -g 400 -p && perf report
>
> 18.09% sched-messaging [kernel.vmlinux] [k] osq_lock
> 12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
> 5.27% sched-messaging [kernel.vmlinux] [k] mutex_unlock
> 3.89% sched-messaging [kernel.vmlinux] [k] wait_consider_task
> 3.64% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
> 3.41% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner.is
> 2.49% sched-messaging [kernel.vmlinux] [k] system_call
>
> We introduce interface bool vcpu_is_preempted(int cpu) and use it in some spin
> loops of osq_lock, rwsem_spin_on_owner and mutex_spin_on_owner.
> These spin_on_onwer variant also cause rcu stall before we apply this patch set
>
> We also have observed some performace improvements in uninx benchmark tests.
>
> PPC test result:
> 1 copy - 0.94%
> 2 copy - 7.17%
> 4 copy - 11.9%
> 8 copy - 3.04%
> 16 copy - 15.11%
>
> details below:
> Without patch:
>
> 1 copy - File Write 4096 bufsize 8000 maxblocks 2188223.0 KBps (30.0 s, 1 samples)
> 2 copy - File Write 4096 bufsize 8000 maxblocks 1804433.0 KBps (30.0 s, 1 samples)
> 4 copy - File Write 4096 bufsize 8000 maxblocks 1237257.0 KBps (30.0 s, 1 samples)
> 8 copy - File Write 4096 bufsize 8000 maxblocks 1032658.0 KBps (30.0 s, 1 samples)
> 16 copy - File Write 4096 bufsize 8000 maxblocks 768000.0 KBps (30.1 s, 1 samples)
>
> With patch:
>
> 1 copy - File Write 4096 bufsize 8000 maxblocks 2209189.0 KBps (30.0 s, 1 samples)
> 2 copy - File Write 4096 bufsize 8000 maxblocks 1943816.0 KBps (30.0 s, 1 samples)
> 4 copy - File Write 4096 bufsize 8000 maxblocks 1405591.0 KBps (30.0 s, 1 samples)
> 8 copy - File Write 4096 bufsize 8000 maxblocks 1065080.0 KBps (30.0 s, 1 samples)
> 16 copy - File Write 4096 bufsize 8000 maxblocks 904762.0 KBps (30.0 s, 1 samples)
>
> X86 test result:
> test-case after-patch before-patch
> Execl Throughput | 18307.9 lps | 11701.6 lps
> File Copy 1024 bufsize 2000 maxblocks | 1352407.3 KBps | 790418.9 KBps
> File Copy 256 bufsize 500 maxblocks | 367555.6 KBps | 222867.7 KBps
> File Copy 4096 bufsize 8000 maxblocks | 3675649.7 KBps | 1780614.4 KBps
> Pipe Throughput | 11872208.7 lps | 11855628.9 lps
> Pipe-based Context Switching | 1495126.5 lps | 1490533.9 lps
> Process Creation | 29881.2 lps | 28572.8 lps
> Shell Scripts (1 concurrent) | 23224.3 lpm | 22607.4 lpm
> Shell Scripts (8 concurrent) | 3531.4 lpm | 3211.9 lpm
> System Call Overhead | 10385653.0 lps | 10419979.0 lps
>
> Christian Borntraeger (1):
> s390/spinlock: Provide vcpu_is_preempted
>
> Juergen Gross (1):
> x86, xen: support vcpu preempted check
>
> Pan Xinhui (9):
> kernel/sched: introduce vcpu preempted check interface
> locking/osq: Drop the overload of osq_lock()
> kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner
> powerpc/spinlock: support vcpu preempted check
> x86, paravirt: Add interface to support kvm/xen vcpu preempted check
> KVM: Introduce kvm_write_guest_offset_cached
> x86, kvm/x86.c: support vcpu preempted check
> x86, kernel/kvm.c: support vcpu preempted check
> Documentation: virtual: kvm: Support vcpu preempted check
>
> Documentation/virtual/kvm/msr.txt | 9 ++++++++-
> arch/powerpc/include/asm/spinlock.h | 8 ++++++++
> arch/s390/include/asm/spinlock.h | 8 ++++++++
> arch/s390/kernel/smp.c | 9 +++++++--
> arch/s390/lib/spinlock.c | 25 ++++++++-----------------
> arch/x86/include/asm/paravirt_types.h | 2 ++
> arch/x86/include/asm/spinlock.h | 8 ++++++++
> arch/x86/include/uapi/asm/kvm_para.h | 4 +++-
> arch/x86/kernel/kvm.c | 12 ++++++++++++
> arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++
> arch/x86/kvm/x86.c | 16 ++++++++++++++++
> arch/x86/xen/spinlock.c | 3 ++-
> include/linux/kvm_host.h | 2 ++
> include/linux/sched.h | 12 ++++++++++++
> kernel/locking/mutex.c | 15 +++++++++++++--
> kernel/locking/osq_lock.c | 10 +++++++++-
> kernel/locking/rwsem-xadd.c | 16 +++++++++++++---
> virt/kvm/kvm_main.c | 20 ++++++++++++++------
> 18 files changed, 151 insertions(+), 34 deletions(-)
>
> --
> 2.4.11
>
>
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