change from v6:
fix typos and remove uncessary comments.
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.
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 | 13 +++++++++++--
kernel/locking/osq_lock.c | 8 +++++++-
kernel/locking/rwsem-xadd.c | 14 +++++++++++---
virt/kvm/kvm_main.c | 20 ++++++++++++++------
18 files changed, 145 insertions(+), 34 deletions(-)
--
2.4.11
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