Re: [PATCH v3 3/3] powerpc/xmon: add debugfs entry for xmon

在 2017/2/21 09:58, Guilherme G. Piccoli 写道: Currently the xmon debugger is set only via kernel boot command-line. It's disabled by default, and can be enabled with "xmon=on" on the command-line. Also, xmon may be accessed via sysrq mechanism. But we cannot enable/disable xmon in runtime, it

Re: [PATCH] powerpc/xmon: Fix an unexpected xmon onoff state change

在 2017/2/17 14:05, Michael Ellerman 写道: Pan Xinhui <xin...@linux.vnet.ibm.com> writes: diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 9c0e17c..f6e5c3d 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -76,6 +76,7 @@ static int xmon_gate;

Re: [PATCH] powerpc/xmon: Fix an unexpected xmon onoff state change

在 2017/2/16 18:57, Guilherme G. Piccoli 写道: On 16/02/2017 03:09, Michael Ellerman wrote: Pan Xinhui <xinhui@linux.vnet.ibm.com> writes: Once xmon is triggered by sysrq-x, it is enabled always afterwards even if it is disabled during boot. This will cause a system reset interru

[PATCH] powerpc/xmon: Fix an unexpected xmon onoff state change

Once xmon is triggered by sysrq-x, it is enabled always afterwards even if it is disabled during boot. This will cause a system reset interrut fail to dump. So keep xmon in its original state after exit. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/xmon/xmon

Re: [PATCH] powerpc/xmon: add debugfs entry for xmon

在 2017/2/14 10:35, Nicholas Piggin 写道: On Mon, 13 Feb 2017 19:00:42 -0200 "Guilherme G. Piccoli" wrote: Currently the xmon debugger is set only via kernel boot command-line. It's disabled by default, and can be enabled with "xmon=on" on the command-line. Also,

[PATCH] powerpc/xmon: add turn off xmon option

commands. Turn xmon off if 'z' is following. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/xmon/xmon.c | 12 +--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 9c0e17c..2f4e7b1

[PATCH v9 6/6] powerpc/pv-qspinlock: Optimise native unlock path

Avoid a function call under native version of qspinlock. On powerNV, bafore applying this patch, every unlock is expensive. This small optimizes enhance the performance. We use static_key with jump_lable which removes unnecessary loads of lppaca and its stuff. Signed-off-by: Pan Xinhui <xin

[PATCH v9 5/6] powerpc: pSeries: Add pv-qspinlock build config/make

pSeries run as a guest and might need pv-qspinlock. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/kernel/Makefile | 1 + arch/powerpc/platforms/pseries/Kconfig | 8 2 files changed, 9 insertions(+) diff --git a/arch/powerpc/kernel/Makefile

[PATCH v9 4/6] powerpc/pv-qspinlock: powerpc support pv-qspinlock

in the hash table might not be the correct lock holder, as for performace issue, we does not take care of hash conflict. Also introduce spin_lock_holder, which tells who owns the lock now. currently the only user is spin_unlock_wait. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.

[PATCH v9 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function

will introduce latency and a little overhead. And we do NOT want to suffer any latency on some cases, e.g. in interrupt handler. The second parameter *confer* can indicate such case. __spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its current vcpu state. Signed-off-by: Pan

[PATCH v9 2/6] powerpc: platforms/Kconfig: Add qspinlock build config

pSeries/powerNV will use qspinlock from now on. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/platforms/Kconfig | 9 + 1 file changed, 9 insertions(+) diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig index fbdae83..3559bbf

[PATCH v9 1/6] powerpc/qspinlock: powerpc support qspinlock

endianness system. We override some arch_spin_XXX as powerpc has io_sync stuff which makes sure the io operations are protected by the lock correctly. There is another special case, see commit 2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more") Signed-off-by: Pan Xinh

[PATCH v9 0/6] Implement qspinlock/pv-qspinlock on ppc

1050.6 ---- Pan Xinhui (6): powerpc/qspinlock: powerpc support qspinlock powerpc: platforms/Kconfig: Add qspinlock build config powerpc: lib/locks.c: Add cpu yield/wake helper function powerpc/pv-qspinlock: powerpc support pv-qspinlo

Re: [PATCH v8 2/6] powerpc: pSeries/Kconfig: Add qspinlock build config

在 2016/12/6 09:24, Pan Xinhui 写道: 在 2016/12/6 08:58, Boqun Feng 写道: On Mon, Dec 05, 2016 at 10:19:22AM -0500, Pan Xinhui wrote: pSeries/powerNV will use qspinlock from now on. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/platforms/pseries/Kconf

Re: [PATCH v8 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function

在 2016/12/6 09:23, Boqun Feng 写道: On Mon, Dec 05, 2016 at 10:19:23AM -0500, Pan Xinhui wrote: Add two corresponding helper functions to support pv-qspinlock. For normal use, __spin_yield_cpu will confer current vcpu slices to the target vcpu(say, a lock holder). If target vcpu

Re: [PATCH v8 2/6] powerpc: pSeries/Kconfig: Add qspinlock build config

在 2016/12/6 08:58, Boqun Feng 写道: On Mon, Dec 05, 2016 at 10:19:22AM -0500, Pan Xinhui wrote: pSeries/powerNV will use qspinlock from now on. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/platforms/pseries/Kconfig | 8 1 file changed, 8 inse

Re: [PATCH v8 1/6] powerpc/qspinlock: powerpc support qspinlock

correct waiman's address. 在 2016/12/6 08:47, Boqun Feng 写道: On Mon, Dec 05, 2016 at 10:19:21AM -0500, Pan Xinhui wrote: This patch add basic code to enable qspinlock on powerpc. qspinlock is one kind of fairlock implementation. And seen some performance improvement under some scenarios

[PATCH v8 6/6] powerpc/pv-qspinlock: Optimise native unlock path

Avoid a function call under native version of qspinlock. On powerNV, bafore applying this patch, every unlock is expensive. This small optimizes enhance the performance. We use static_key with jump_label which removes unnecessary loads of lppaca and its stuff. Signed-off-by: Pan Xinhui <xin

[PATCH v8 5/6] powerpc: pSeries: Add pv-qspinlock build config/make

pSeries run as a guest and might need pv-qspinlock. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/kernel/Makefile | 1 + arch/powerpc/platforms/pseries/Kconfig | 8 2 files changed, 9 insertions(+) diff --git a/arch/powerpc/kernel/Makefile

[PATCH v8 4/6] powerpc/pv-qspinlock: powerpc support pv-qspinlock

in the hash table might not be the correct lock holder, as for performace issue, we does not take care of hash conflict. Also introduce spin_lock_holder, which tells who owns the lock now. currently the only user is spin_unlock_wait. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.

[PATCH v8 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function

will introduce latency and a little overhead. And we do NOT want to suffer any latency on some cases, e.g. in interrupt handler. The second parameter *confer* can indicate such case. __spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its current vcpu state. Signed-off-by: Pan

[PATCH v8 2/6] powerpc: pSeries/Kconfig: Add qspinlock build config

pSeries/powerNV will use qspinlock from now on. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/platforms/pseries/Kconfig | 8 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig

[PATCH v8 1/6] powerpc/qspinlock: powerpc support qspinlock

endianness system. We override some arch_spin_XXX as powerpc has io_sync stuff which makes sure the io operations are protected by the lock correctly. There is another special case, see commit 2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more") Signed-off-by: Pan Xinh

[PATCH v8 0/6] Implement qspinlock/pv-qspinlock on ppc

1134.2 = System Benchmarks Index Score 1072.0 1108.91050.6 -------- Pan Xinhui (6): powerpc/qspinlock: powerpc support qspinlock powerpc

Re: [PATCH] powerpc: cputime: fix a compile warning

在 2016/12/2 12:35, yjin 写道: On 2016年12月02日 12:22, Balbir Singh wrote: On Fri, Dec 2, 2016 at 3:15 PM, Michael Ellerman wrote: yanjiang@windriver.com writes: diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h index

Re: [PATCH] powerpc: Fix __cmpxchg() to take a volatile ptr again

在 2016/11/25 11:07, Michael Ellerman 写道: In commit d0563a1297e2 ("powerpc: Implement {cmp}xchg for u8 and u16") we removed the volatile from __cmpxchg(). This is leading to warnings such as: drivers/gpu/drm/drm_lock.c: In function ‘drm_lock_take’:

Re: [PATCH v7 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

在 2016/11/16 18:23, Peter Zijlstra 写道: On Wed, Nov 16, 2016 at 12:19:09PM +0800, Pan Xinhui wrote: Hi, Peter. I think we can avoid a function call in a simpler way. How about below static inline bool vcpu_is_preempted(int cpu) { /* only set in pv case

Re: [PATCH v7 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

在 2016/11/15 23:47, Peter Zijlstra 写道: On Wed, Nov 02, 2016 at 05:08:33AM -0400, Pan Xinhui wrote: diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 0f400c0..38c3bb7 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm

[PATCH v7 11/11] Documentation: virtual: kvm: Support vcpu preempted check

u has been preempted. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Radim Krčmář <rkrc...@redhat.com> Acked-by: Paolo Bonzini <pbonz...@redhat.com> --- Documentation/virtual/kvm/msr.txt | 9 - 1 file changed, 8 insertions(+), 1 deletion(-) diff --git

[PATCH v7 10/11] x86, xen: support vcpu preempted check

early yielding. A quick test (4 vcpus on 1 physical cpu doing a parallel build job with "make -j 8") reduced system time by about 5% with this patch. Signed-off-by: Juergen Gross <jgr...@suse.com> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/xe

[PATCH v7 09/11] x86, kernel/kvm.c: support vcpu preempted check

concurrent) | 3531.4 lpm | 3211.9 lpm System Call Overhead | 10385653.0 lps | 10419979.0 lps Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonz...@redhat.com> --- arch/x86/kernel/kvm.c | 12 1 file

[PATCH v7 08/11] x86, kvm/x86.c: support vcpu preempted check

kvm_steal_time ::preempted to indicate that if one vcpu is running or not. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonz...@redhat.com> --- arch/x86/include/uapi/asm/kvm_para.h | 4 +++- arch/x86/kvm/x86.c | 16 +

[PATCH v7 07/11] KVM: Introduce kvm_write_guest_offset_cached

It allows us to update some status or field of one struct partially. We can also save one kvm_read_guest_cached if we just update one filed of the struct regardless of its current value. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonz...@r

[PATCH v7 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

the spin loops upon the retval of vcpu_is_preempted. As kernel has used this interface, So lets support it. To deal with kernel and kvm/xen, add vcpu_is_preempted into struct pv_lock_ops. Then kvm or xen could provide their own implementation to support vcpu_is_preempted. Signed-off-by: Pan Xinhui

[PATCH v7 05/11] s390/spinlock: Provide vcpu_is_preempted

From: Christian Borntraeger this implements the s390 backend for commit "kernel/sched: introduce vcpu preempted check interface" by reworking the existing smp_vcpu_scheduled into arch_vcpu_is_preempted. We can then also get rid of the local cpu_is_preempted function by

[PATCH v7 04/11] powerpc/spinlock: support vcpu preempted check

->yiled_count keeps zero on PowerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/include/asm/spinlock.h

[PATCH v7 03/11] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Acked-by: Paolo Bonzini <pbonz...@redhat.com> Tested-by: Juer

[PATCH v7 02/11] locking/osq: Drop the overload of osq_lock()

call_common 2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Suggested-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui@linux

[PATCH v7 01/11] kernel/sched: introduce vcpu preempted check interface

. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Acked-by: Paolo Bonzini <pbonz...@redhat.com> Tested-by: Juergen Gross <jgr...@suse.com> -

[PATCH v7 00/11] implement vcpu preempted check

tem 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/o

Re: [PATCH v6 02/11] locking/osq: Drop the overload of osq_lock()

在 2016/10/30 00:52, Davidlohr Bueso 写道: On Fri, 28 Oct 2016, Pan Xinhui wrote: /* * If we need to reschedule bail... so we can block. + * Use vcpu_is_preempted to detech lock holder preemption issue ^^ detect ok. thanks

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

在 2016/10/29 03:38, Konrad Rzeszutek Wilk 写道: 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

Re: [Xen-devel] [PATCH v6 10/11] x86, xen: support vcpu preempted check

在 2016/10/29 03:43, Konrad Rzeszutek Wilk 写道: On Fri, Oct 28, 2016 at 04:11:26AM -0400, Pan Xinhui wrote: From: Juergen Gross <jgr...@suse.com> Support the vcpu_is_preempted() functionality under Xen. This will enhance lock performance on overcommitted hosts (more runnable vcpu

[PATCH v6 11/11] Documentation: virtual: kvm: Support vcpu preempted check

u has been preempted. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Radim Krčmář <rkrc...@redhat.com> --- Documentation/virtual/kvm/msr.txt | 9 - 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/v

[PATCH v6 10/11] x86, xen: support vcpu preempted check

early yielding. A quick test (4 vcpus on 1 physical cpu doing a parallel build job with "make -j 8") reduced system time by about 5% with this patch. Signed-off-by: Juergen Gross <jgr...@suse.com> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/xe

[PATCH v6 09/11] x86, kernel/kvm.c: support vcpu preempted check

concurrent) | 3531.4 lpm | 3211.9 lpm System Call Overhead | 10385653.0 lps | 10419979.0 lps Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/kernel/kvm.c | 12 1 file changed, 12 insertions(+) diff --git a/arch/x86/ker

[PATCH v6 08/11] x86, kvm/x86.c: support vcpu preempted check

kvm_steal_time ::preempted to indicate that if one vcpu is running or not. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/include/uapi/asm/kvm_para.h | 4 +++- arch/x86/kvm/x86.c | 16 2 files changed, 19 insertions(+), 1 deletion(-)

[PATCH v6 07/11] KVM: Introduce kvm_write_guest_offset_cached

It allows us to update some status or field of one struct partially. We can also save one kvm_read_guest_cached if we just update one filed of the struct regardless of its current value. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- include/linux/kvm_host.h | 2 ++ vi

[PATCH v6 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

the spin loops upon on the retval of vcpu_is_preempted. As kernel has used this interface, So lets support it. To deal with kernel and kvm/xen, add vcpu_is_preempted into struct pv_lock_ops. Then kvm or xen could provide their own implementation to support vcpu_is_preempted. Signed-off-by: Pan

[PATCH v6 05/11] s390/spinlock: Provide vcpu_is_preempted

From: Christian Borntraeger this implements the s390 backend for commit "kernel/sched: introduce vcpu preempted check interface" by reworking the existing smp_vcpu_scheduled into arch_vcpu_is_preempted. We can then also get rid of the local cpu_is_preempted function by

[PATCH v6 04/11] powerpc/spinlock: support vcpu preempted check

->yiled_count keeps zero on powerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/include/asm/spinl

[PATCH v6 03/11] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Tested-by: Juergen Gross <jgr...@suse.com> --- kernel

[PATCH v6 02/11] locking/osq: Drop the overload of osq_lock()

call_common 2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Suggested-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui@linux

[PATCH v6 01/11] kernel/sched: introduce vcpu preempted check interface

. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Tested-by: Juergen Gross <jgr...@suse.com> --- include/linux/sched.h | 12 1 fil

[PATCH v6 00/11] implement vcpu preempted check

79.0 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 o

Re: [PATCH v4 5/5] x86, kvm: support vcpu preempted check

在 2016/10/24 23:18, Paolo Bonzini 写道: On 24/10/2016 17:14, Radim Krčmář wrote: 2016-10-24 16:39+0200, Paolo Bonzini: On 19/10/2016 19:24, Radim Krčmář wrote: + if (vcpu->arch.st.msr_val & KVM_MSR_ENABLED) + if (kvm_read_guest_cached(vcpu->kvm, >arch.st.stime, +

Re: [PATCH v5 9/9] Documentation: virtual: kvm: Support vcpu preempted check

在 2016/10/21 09:23, Boqun Feng 写道: On Thu, Oct 20, 2016 at 05:27:54PM -0400, Pan Xinhui wrote: Commit ("x86, kvm: support vcpu preempted check") add one field "__u8 preempted" into struct kvm_steal_time. This field tells if one vcpu is running or not. It is zero if

[PATCH v5 9/9] Documentation: virtual: kvm: Support vcpu preempted check

n preempted. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- Documentation/virtual/kvm/msr.txt | 8 +++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/virtual/kvm/msr.txt index 2a71c8f..3376f13 100644 --- a

[PATCH v5 8/9] s390/spinlock: Provide vcpu_is_preempted

From: Christian Borntraeger this implements the s390 backend for commit "kernel/sched: introduce vcpu preempted check interface" by reworking the existing smp_vcpu_scheduled into arch_vcpu_is_preempted. We can then also get rid of the local cpu_is_preempted function by

[PATCH v5 7/9] x86, xen: support vcpu preempted check

early yielding. A quick test (4 vcpus on 1 physical cpu doing a parallel build job with "make -j 8") reduced system time by about 5% with this patch. Signed-off-by: Juergen Gross <jgr...@suse.com> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/xe

[PATCH v5 6/9] x86, kvm: support vcpu preempted check

Call Overhead | 10385653.0 lps | 10419979.0 lps Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/include/uapi/asm/kvm_para.h | 3 ++- arch/x86/kernel/kvm.c| 12 arch/x86/kvm/x86.c | 18 +++

[PATCH v5 5/9] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

the spin loops upon on the retval of vcpu_is_preempted. As kernel has used this interface, So lets support it. To deal with kernel and kvm/xen, add vcpu_is_preempted into struct pv_lock_ops. Then kvm or xen could provide their own implementation to support vcpu_is_preempted. Signed-off-by: Pan

[PATCH v5 4/9] powerpc/spinlock: support vcpu preempted check

->yiled_count keeps zero on powerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/include/asm/spinl

[PATCH v5 3/9] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Tested-by: Juergen Gross <jgr...@suse.com> --- kernel

[PATCH v5 2/9] locking/osq: Drop the overload of osq_lock()

call_common 2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Suggested-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui@linux

[PATCH v5 1/9] kernel/sched: introduce vcpu preempted check interface

. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com> Tested-by: Juergen Gross <jgr...@suse.com> --- include/linux/sched.h | 12 1 fil

[PATCH v5 0/9] implement vcpu preempted check

ripts (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 (7): kernel/sched: i

Re: [PATCH v4 5/5] x86, kvm: support vcpu preempted check

在 2016/10/20 01:24, Radim Krčmář 写道: 2016-10-19 06:20-0400, Pan Xinhui: This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu

Re: [PATCH v4 0/5] implement vcpu preempted check

在 2016/10/19 23:58, Juergen Gross 写道: On 19/10/16 12:20, Pan Xinhui wrote: 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

Re: [PATCH v4 0/5] implement vcpu preempted check

在 2016/10/19 14:47, Christian Borntraeger 写道: On 10/19/2016 12:20 PM, Pan Xinhui wrote: change from v3: add x86 vcpu preempted check patch If you want you could add the s390 patch that I provided for your last version. I also gave my Acked-by for all previous patches. hi

[PATCH v4 5/5] x86, kvm: support vcpu preempted check

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 Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/x86/inclu

[PATCH v4 4/5] powerpc/spinlock: support vcpu preempted check

->yiled_count keeps zero on powerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/include/asm/spinl

[PATCH v4 3/5] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- kernel/locking/mutex.c | 15 +-- kernel/locking/rwsem-xadd.c | 16 +--- 2 files changed, 26 in

[PATCH v4 2/5] locking/osq: Drop the overload of osq_lock()

call_common 2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Suggested-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui...

[PATCH v4 0/5] implement vcpu preempted check

ncurrent) |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 Pan Xinhui (5): kernel/sched: introduce vcpu preempted check interface locking/osq: Drop the

[PATCH v4 1/5] kernel/sched: introduce vcpu preempted check interface

. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- include/linux/sched.h | 12 1 file changed, 12 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 348f51b..44

Re: [PATCH v3 0/4] implement vcpu preempted check

在 2016/9/30 17:08, Paolo Bonzini 写道: On 30/09/2016 10:52, Pan Xinhui wrote: x86 has no hypervisor support, and I'd like to understand the desired semantics first, so I don't think it should block this series. In Once a guest do a hypercall or something similar, IOW

Re: [PATCH v3 0/4] implement vcpu preempted check

hi, Paolo thanks for your reply. 在 2016/9/30 14:58, Paolo Bonzini 写道: Please consider s390 and (x86/arm) KVM. Once we have a few, more can follow later, but I think its important to not only have PPC support for this. Actually the s390 preemted check via sigp sense running is

Re: [PATCH v3 0/4] implement vcpu preempted check

在 2016/9/29 18:31, Peter Zijlstra 写道: On Thu, Sep 29, 2016 at 12:23:19PM +0200, Christian Borntraeger wrote: On 09/29/2016 12:10 PM, Peter Zijlstra wrote: On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote: change from v2: no code change, fix typos, update some comments

Re: [PATCH v3 0/4] implement vcpu preempted check

在 2016/9/29 18:10, Peter Zijlstra 写道: On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote: 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

[PATCH v7 6/6] powerpc: pSeries: Add pv-qspinlock build config/make

pSeries run as a guest and might need pv-qspinlock. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/kernel/Makefile | 1 + arch/powerpc/platforms/pseries/Kconfig | 8 2 files changed, 9 insertions(+) diff --git a/arch/powerpc/kernel/Makefile

[PATCH v7 5/6] powerpc/pv-qspinlock: powerpc support pv-qspinlock

in the hash table might not be the correct lock holder, as for performace issue, we does not take care of hash conflict. Also introduce spin_lock_holder, which tells who owns the lock now. currently the only user is spin_unlock_wait. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.

[PATCH v7 4/6] powerpc: lib/locks.c: Add cpu yield/wake helper function

will introduce latency and a little overhead. And we do NOT want to suffer any latency on some cases, e.g. in interrupt handler. The second parameter *confer* can indicate such case. __spin_wake_cpu is simpiler, it will wake up one vcpu regardless of its current vcpu state. Signed-off-by: Pan

[PATCH v7 3/6] powerpc: pseries/Kconfig: Add qspinlock build config

pseries will use qspinlock by default. Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/platforms/pseries/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index bec90fb..f

[PATCH v7 2/6] powerpc/qspinlock: powerpc support qspinlock

two endianness system. We override some arch_spin_xxx as powerpc has io_sync stuff which makes sure the io operations are protected by the lock correctly. There is another special case, see commit 2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more") Signed-off-by: Pan X

[PATCH v7 1/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock

-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- kernel/locking/qspinlock_paravirt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 8a99

[PATCH v7 0/6] Implement qspinlock/pv-qspinlock on ppc

1008.3 1122.61134.2 = System Benchmarks Index Score 1072.0 1108.91050.6 -------- Pan Xinhui (6): pv-qspin

[PATCH v3 0/4] implement vcpu preempted check

ace 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 Pan Xinhui (4): kernel/sched: introduce vcpu preempted check interface powerpc/spinlock: support vcpu p

[PATCH v3 3/4] locking/osq: Drop the overhead of osq_lock()

call_common 2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Suggested-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui...

[PATCH v3 4/4] kernel/locking: Drop the overhead of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- kernel/locking/mutex.c | 15 +-- kernel/locking/rwsem-xadd.c | 16 +--- 2 files changed, 26 in

[PATCH v3 2/4] powerpc/spinlock: support vcpu preempted check

->yield_count keeps zero on powerNV. So we can just skip the machine type check. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/includ

[PATCH v3 1/4] kernel/sched: introduce vcpu preempted check interface

check. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- include/linux/sched.h | 12 1 file changed, 12 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 6e42ada..cb

Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check

Hi, Baibir sorry for late responce, I missed reading your mail. 在 16/7/6 18:54, Balbir Singh 写道: On Tue, 2016-06-28 at 10:43 -0400, Pan Xinhui wrote: This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself

[PATCH v2 4/4] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

essaging [kernel.vmlinux] [k] system_call 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- kernel/locking/mutex.c | 15 +-- kernel/locking/rwsem-xadd.c | 16 +--- 2 files changed, 26 in

[PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check

->yiled_count keeps zero on powerNV. So we can just skip the machine type. Suggested-by: Boqun Feng <boqun.f...@gmail.com> Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/includ

[PATCH v2 1/4] kernel/sched: introduce vcpu preempted check interface

. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- include/linux/sched.h | 12 1 file changed, 12 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 6e42ada..cb

[PATCH v2 0/4] implement vcpu preempted check

tem_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 Pan Xinhui (4): kernel/sched: introduce vcpu preempted check i

[PATCH 0/3] implement vcpu preempted check

so need fix other XXX_spin_on_owner later based on this patch set. these spin_on_onwer variant cause rcu stall. Pan Xinhui (3): powerpc/spinlock: support vcpu preempted check locking/osq: Drop the overload of osq_lock() kernel/sched: introduce vcpu preempted check interface arch/powerpc/

[PATCH 3/3] locking/osq: Drop the overload of osq_lock()

mlinux] [k] copypage_power7 2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner 2.00% sched-messaging [kernel.vmlinux] [k] osq_lock Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- kernel/locking/osq_lock.c | 16 +++- 1 file changed, 15 insertio

[PATCH 2/3] powerpc/spinlock: support vcpu preempted check

n.f...@gmail.com> Signed-off-by: Pan Xinhui <xinhui@linux.vnet.ibm.com> --- arch/powerpc/include/asm/lppaca.h | 6 ++ arch/powerpc/include/asm/spinlock.h | 15 +++ 2 files changed, 21 insertions(+) diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/

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