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[PATCH v4 0/5] implement vcpu preempted check

Started byPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
First post2016-10-19 08:30 +0200
Last post2016-10-19 19:10 +0200
Articles 7 — 4 participants

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Contents

  [PATCH v4 0/5] implement vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-19 08:30 +0200
    [PATCH v4 4/5] powerpc/spinlock: support vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-19 08:30 +0200
    [PATCH v4 1/5] kernel/sched: introduce vcpu preempted check interface Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-19 08:30 +0200
    [PATCH v4 2/5] locking/osq: Drop the overload of osq_lock() Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-19 08:30 +0200
    Re: [PATCH v4 0/5] implement vcpu preempted check Christian Borntraeger <borntraeger@de.ibm.com> - 2016-10-19 08:50 +0200
    Re: [PATCH v4 0/5] implement vcpu preempted check Juergen Gross <jgross@suse.com> - 2016-10-19 18:00 +0200
      Re: [PATCH v4 0/5] implement vcpu preempted check Pan Xinhui <xinhui@linux.vnet.ibm.com> - 2016-10-19 19:10 +0200

#1503574 — [PATCH v4 0/5] implement vcpu preempted check

FromPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Date2016-10-19 08:30 +0200
Subject[PATCH v4 0/5] implement vcpu preempted check
Message-ID<stSxX-5F5-5@gated-at.bofh.it>
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.

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 

Pan Xinhui (5):
  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, kvm: support vcpu preempted check

 arch/powerpc/include/asm/spinlock.h   |  8 ++++++++
 arch/x86/include/asm/paravirt_types.h |  6 ++++++
 arch/x86/include/asm/spinlock.h       |  8 ++++++++
 arch/x86/include/uapi/asm/kvm_para.h  |  3 ++-
 arch/x86/kernel/kvm.c                 | 11 +++++++++++
 arch/x86/kernel/paravirt.c            | 11 +++++++++++
 arch/x86/kvm/x86.c                    | 12 ++++++++++++
 include/linux/sched.h                 | 12 ++++++++++++
 kernel/locking/mutex.c                | 15 +++++++++++++--
 kernel/locking/osq_lock.c             | 10 +++++++++-
 kernel/locking/rwsem-xadd.c           | 16 +++++++++++++---
 11 files changed, 105 insertions(+), 7 deletions(-)

-- 
2.4.11

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#1503575 — [PATCH v4 4/5] powerpc/spinlock: support vcpu preempted check

FromPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Date2016-10-19 08:30 +0200
Subject[PATCH v4 4/5] powerpc/spinlock: support vcpu preempted check
Message-ID<stSxX-5F5-11@gated-at.bofh.it>
In reply to#1503574
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 as parameter and return true if the cpu is preempted. Then
kernel can break the spin loops upon on the retval of vcpu_is_preempted.

As kernel has used this interface, So lets support it.

Only pSeries need support it. And the fact is powerNV are built into
same kernel image with pSeries. So we need return false if we are runnig
as powerNV. The another fact is that lppaca->yiled_count keeps zero on
powerNV. So we can just skip the machine type check.

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/spinlock.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index abb6b0f..af4285b 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -52,6 +52,14 @@
 #define SYNC_IO
 #endif
 
+#ifdef CONFIG_PPC_PSERIES
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(int cpu)
+{
+	return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1);
+}
+#endif
+
 #if defined(CONFIG_PPC_SPLPAR)
 /* We only yield to the hypervisor if we are in shared processor mode */
 #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
-- 
2.4.11

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#1503577 — [PATCH v4 1/5] kernel/sched: introduce vcpu preempted check interface

FromPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Date2016-10-19 08:30 +0200
Subject[PATCH v4 1/5] kernel/sched: introduce vcpu preempted check interface
Message-ID<stSxY-5F5-19@gated-at.bofh.it>
In reply to#1503574
This patch support to fix lock holder preemption issue.

For kernel users, we could use bool vcpu_is_preempted(int cpu) to detech if
one vcpu is preempted or not.

The default implementation is a macro defined by false. So compiler can
wrap it out if arch dose not support such vcpu pteempted check.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@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..44c1ce7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -3506,6 +3506,18 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
 
 #endif /* CONFIG_SMP */
 
+/*
+ * In order to deal with a various lock holder preemption issues provide an
+ * interface to see if a vCPU is currently running or not.
+ *
+ * This allows us to terminate optimistic spin loops and block, analogous to
+ * the native optimistic spin heuristic of testing if the lock owner task is
+ * running or not.
+ */
+#ifndef vcpu_is_preempted
+#define vcpu_is_preempted(cpu)	false
+#endif
+
 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
 
-- 
2.4.11

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#1503578 — [PATCH v4 2/5] locking/osq: Drop the overload of osq_lock()

FromPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Date2016-10-19 08:30 +0200
Subject[PATCH v4 2/5] locking/osq: Drop the overload of osq_lock()
Message-ID<stSxY-5F5-21@gated-at.bofh.it>
In reply to#1503574
An over-committed guest with more vCPUs than pCPUs has a heavy overload in
osq_lock().

This is because vCPU A hold the osq lock and yield out, vCPU B wait per_cpu
node->locked to be set. IOW, vCPU B wait vCPU A to run and unlock the osq
lock.

Kernel has an interface bool vcpu_is_preempted(int cpu) to see if a vCPU is
currently running or not. So break the spin loops on true condition.

test case:
perf record -a perf bench sched messaging -g 400 -p && perf report

before patch:
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

after patch:
20.68%  sched-messaging  [kernel.vmlinux]  [k] mutex_spin_on_owner
 8.45%  sched-messaging  [kernel.vmlinux]  [k] mutex_unlock
 4.12%  sched-messaging  [kernel.vmlinux]  [k] system_call
 3.01%  sched-messaging  [kernel.vmlinux]  [k] system_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.feng@gmail.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
 kernel/locking/osq_lock.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index 05a3785..39d1385 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -21,6 +21,11 @@ static inline int encode_cpu(int cpu_nr)
 	return cpu_nr + 1;
 }
 
+static inline int node_cpu(struct optimistic_spin_node *node)
+{
+	return node->cpu - 1;
+}
+
 static inline struct optimistic_spin_node *decode_cpu(int encoded_cpu_val)
 {
 	int cpu_nr = encoded_cpu_val - 1;
@@ -118,8 +123,11 @@ bool osq_lock(struct optimistic_spin_queue *lock)
 	while (!READ_ONCE(node->locked)) {
 		/*
 		 * If we need to reschedule bail... so we can block.
+		 * Use vcpu_is_preempted to detech lock holder preemption issue
+		 * and break. vcpu_is_preempted is a macro defined by false if
+		 * arch does not support vcpu preempted check,
 		 */
-		if (need_resched())
+		if (need_resched() || vcpu_is_preempted(node_cpu(node->prev)))
 			goto unqueue;
 
 		cpu_relax_lowlatency();
-- 
2.4.11

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#1503583

FromChristian Borntraeger <borntraeger@de.ibm.com>
Date2016-10-19 08:50 +0200
Message-ID<stSRj-5NC-9@gated-at.bofh.it>
In reply to#1503574
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.



> 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.
> 
> 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 
> 
> Pan Xinhui (5):
>   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, kvm: support vcpu preempted check
> 
>  arch/powerpc/include/asm/spinlock.h   |  8 ++++++++
>  arch/x86/include/asm/paravirt_types.h |  6 ++++++
>  arch/x86/include/asm/spinlock.h       |  8 ++++++++
>  arch/x86/include/uapi/asm/kvm_para.h  |  3 ++-
>  arch/x86/kernel/kvm.c                 | 11 +++++++++++
>  arch/x86/kernel/paravirt.c            | 11 +++++++++++
>  arch/x86/kvm/x86.c                    | 12 ++++++++++++
>  include/linux/sched.h                 | 12 ++++++++++++
>  kernel/locking/mutex.c                | 15 +++++++++++++--
>  kernel/locking/osq_lock.c             | 10 +++++++++-
>  kernel/locking/rwsem-xadd.c           | 16 +++++++++++++---
>  11 files changed, 105 insertions(+), 7 deletions(-)
>

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#1504010

FromJuergen Gross <jgross@suse.com>
Date2016-10-19 18:00 +0200
Message-ID<su1rC-3fC-127@gated-at.bofh.it>
In reply to#1503574

[Multipart message — attachments visible in raw view] — view raw

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 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.
> 
> 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 
> 
> Pan Xinhui (5):
>   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, kvm: support vcpu preempted check

The attached patch adds Xen support for x86. Please tell me whether you
want to add this patch to your series or if I should post it when your
series has been accepted.

You can add my

Tested-by: Juergen Gross <jgross@suse.com>

for patches 1-3 and 5 (paravirt parts only).


Juergen

> 
>  arch/powerpc/include/asm/spinlock.h   |  8 ++++++++
>  arch/x86/include/asm/paravirt_types.h |  6 ++++++
>  arch/x86/include/asm/spinlock.h       |  8 ++++++++
>  arch/x86/include/uapi/asm/kvm_para.h  |  3 ++-
>  arch/x86/kernel/kvm.c                 | 11 +++++++++++
>  arch/x86/kernel/paravirt.c            | 11 +++++++++++
>  arch/x86/kvm/x86.c                    | 12 ++++++++++++
>  include/linux/sched.h                 | 12 ++++++++++++
>  kernel/locking/mutex.c                | 15 +++++++++++++--
>  kernel/locking/osq_lock.c             | 10 +++++++++-
>  kernel/locking/rwsem-xadd.c           | 16 +++++++++++++---
>  11 files changed, 105 insertions(+), 7 deletions(-)
>

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#1504146

FromPan Xinhui <xinhui@linux.vnet.ibm.com>
Date2016-10-19 19:10 +0200
Message-ID<su2xj-4eW-7@gated-at.bofh.it>
In reply to#1504010
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 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.
>>
>> 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
>>
>> Pan Xinhui (5):
>>   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, kvm: support vcpu preempted check
>
> The attached patch adds Xen support for x86. Please tell me whether you
> want to add this patch to your series or if I should post it when your
> series has been accepted.
>
hi, Juergen
	Your patch is pretty small and nice :) thanks!
I can include your patch into my next patchset after this patchset reviewed. :)


> You can add my
>
> Tested-by: Juergen Gross <jgross@suse.com>
>
> for patches 1-3 and 5 (paravirt parts only).
>

Thanks a lot!

xinhui

>
> Juergen
>
>>
>>  arch/powerpc/include/asm/spinlock.h   |  8 ++++++++
>>  arch/x86/include/asm/paravirt_types.h |  6 ++++++
>>  arch/x86/include/asm/spinlock.h       |  8 ++++++++
>>  arch/x86/include/uapi/asm/kvm_para.h  |  3 ++-
>>  arch/x86/kernel/kvm.c                 | 11 +++++++++++
>>  arch/x86/kernel/paravirt.c            | 11 +++++++++++
>>  arch/x86/kvm/x86.c                    | 12 ++++++++++++
>>  include/linux/sched.h                 | 12 ++++++++++++
>>  kernel/locking/mutex.c                | 15 +++++++++++++--
>>  kernel/locking/osq_lock.c             | 10 +++++++++-
>>  kernel/locking/rwsem-xadd.c           | 16 +++++++++++++---
>>  11 files changed, 105 insertions(+), 7 deletions(-)
>>
>

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