search for: qspinlock

...feature to support it. We'd provide call site patch space for indirect branches for those out of range of direct call, so that should work fine. The trick would be patching in the TOC lookup for the function... should be doable somehow. Thanks, Nick --- diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h index b752d34517b3..26d8766a1106 100644 --- a/arch/powerpc/include/asm/qspinlock.h +++ b/arch/powerpc/include/asm/qspinlock.h @@ -31,16 +31,57 @@ static inline void queued_spin_unlock(struct qspinlock *lock) #else extern void queued_spin_lock_slowpath(st...

...feature to support it. We'd provide call site patch space for indirect branches for those out of range of direct call, so that should work fine. The trick would be patching in the TOC lookup for the function... should be doable somehow. Thanks, Nick --- diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h index b752d34517b3..26d8766a1106 100644 --- a/arch/powerpc/include/asm/qspinlock.h +++ b/arch/powerpc/include/asm/qspinlock.h @@ -31,16 +31,57 @@ static inline void queued_spin_unlock(struct qspinlock *lock) #else extern void queued_spin_lock_slowpath(st...

...7 benchmark on both ext4 and xfs RAM disks at 3000 users on a 3.15-rc1 based kernel. The "ebizzy -m" test was was also run and its performance data were recorded. With two VMs running, the "idle=poll" kernel option was added to simulate a busy guest. The entry "unfair + PV qspinlock" below means that both the unfair lock and PV spinlock configuration options were turned on. AIM7 XFS Disk Test (no overcommit) kernel JPM Real Time Sys Time Usr Time ----- --- --------- -------- -------- PV ticketlock...

As we need let pv-qspinlock-kernel run on all environment which might have no powervm, we should runtime choose which qspinlock version to use. The default pv-qspinlock use native version. pv_lock initialization should be done in bootstage with irq disabled. And if possible, restore pv_lock_ops callbacks to pv version. Signe...

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v8 -> v9: mv qspinlocm config entry to platforms/kconfig fix comments and re...

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v8 -> v9: mv qspinlocm config entry to platforms/kconfig fix comments and re...

...test-and-set scheme, or to mimic the bare metal behavior. V2: - use static key instead of making virt_spin_lock() a pvops function Juergen Gross (2): paravirt/locks: use new static key for controlling call of virt_spin_lock() paravirt,xen: correct xen_nopvspin case arch/x86/include/asm/qspinlock.h | 11 +++++++++++ arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++ arch/x86/kernel/smpboot.c | 2 ++ arch/x86/xen/spinlock.c | 2 ++ kernel/locking/qspinlock.c | 4 ++++ 5 files changed, 25 insertions(+) -- 2.12.3

...test-and-set scheme, or to mimic the bare metal behavior. V2: - use static key instead of making virt_spin_lock() a pvops function Juergen Gross (2): paravirt/locks: use new static key for controlling call of virt_spin_lock() paravirt,xen: correct xen_nopvspin case arch/x86/include/asm/qspinlock.h | 11 +++++++++++ arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++ arch/x86/kernel/smpboot.c | 2 ++ arch/x86/xen/spinlock.c | 2 ++ kernel/locking/qspinlock.c | 4 ++++ 5 files changed, 25 insertions(+) -- 2.12.3

Signed-off-by: Nicholas Piggin <npiggin at gmail.com> --- arch/powerpc/include/asm/paravirt.h | 28 ++++++++ arch/powerpc/include/asm/qspinlock.h | 66 +++++++++++++++++++ arch/powerpc/include/asm/qspinlock_paravirt.h | 7 ++ arch/powerpc/platforms/pseries/Kconfig | 5 ++ arch/powerpc/platforms/pseries/setup.c | 6 +- include/asm-generic/qspinlock.h | 2 + 6 files changed, 113 insertions(+), 1 delet...

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v7 -> v8: add one patch to drop a function call under native qspinlock unlock...

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v7 -> v8: add one patch to drop a function call under native qspinlock unlock...

On 09/05/2017 09:24 AM, Juergen Gross wrote: > There are cases where a guest tries to switch spinlocks to bare metal > behavior (e.g. by setting "xen_nopvspin" boot parameter). Today this > has the downside of falling back to unfair test and set scheme for > qspinlocks due to virt_spin_lock() detecting the virtualized > environment. > > Make virt_spin_lock() a paravirt operation in order to enable users > to select an explicit behavior like bare metal. > > Signed-off-by: Juergen Gross <jgross at suse.com> > --- > arch/x86/include/a...

On 09/05/2017 09:24 AM, Juergen Gross wrote: > There are cases where a guest tries to switch spinlocks to bare metal > behavior (e.g. by setting "xen_nopvspin" boot parameter). Today this > has the downside of falling back to unfair test and set scheme for > qspinlocks due to virt_spin_lock() detecting the virtualized > environment. > > Make virt_spin_lock() a paravirt operation in order to enable users > to select an explicit behavior like bare metal. > > Signed-off-by: Juergen Gross <jgross at suse.com> > --- > arch/x86/include/a...

Signed-off-by: Nicholas Piggin <npiggin at gmail.com> --- arch/powerpc/include/asm/paravirt.h | 23 ++++++++ arch/powerpc/include/asm/qspinlock.h | 55 +++++++++++++++++++ arch/powerpc/include/asm/qspinlock_paravirt.h | 5 ++ arch/powerpc/platforms/pseries/Kconfig | 5 ++ arch/powerpc/platforms/pseries/setup.c | 6 +- include/asm-generic/qspinlock.h | 2 + 6 files changed, 95 insertions(+), 1 deleti...

From: root <root at ltcalpine2-lp13.aus.stglabs.ibm.com> change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch cover letter tilte has changed as only pseries...

From: root <root at ltcalpine2-lp13.aus.stglabs.ibm.com> change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch cover letter tilte has changed as only pseries...

Signed-off-by: Nicholas Piggin <npiggin at gmail.com> --- arch/powerpc/include/asm/paravirt.h | 28 ++++++++++ arch/powerpc/include/asm/qspinlock.h | 55 +++++++++++++++++++ arch/powerpc/include/asm/qspinlock_paravirt.h | 5 ++ arch/powerpc/platforms/pseries/Kconfig | 5 ++ arch/powerpc/platforms/pseries/setup.c | 6 +- include/asm-generic/qspinlock.h | 2 + 6 files changed, 100 insertions(+), 1 delet...

v8->v9: - Integrate PeterZ's version of the queue spinlock patch with some modification: http://lkml.kernel.org/r/20140310154236.038181843 at infradead.org - Break the more complex patches into smaller ones to ease review effort. - Fix a racing condition in the PV qspinlock code. v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit to enable/disable unfair lock. - Reduce unfair lock slowpath lock stealing fr...

v8->v9: - Integrate PeterZ's version of the queue spinlock patch with some modification: http://lkml.kernel.org/r/20140310154236.038181843 at infradead.org - Break the more complex patches into smaller ones to ease review effort. - Fix a racing condition in the PV qspinlock code. v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit to enable/disable unfair lock. - Reduce unfair lock slowpath lock stealing fr...

On 7/21/20 7:08 AM, Nicholas Piggin wrote: > diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h > index b752d34517b3..26d8766a1106 100644 > --- a/arch/powerpc/include/asm/qspinlock.h > +++ b/arch/powerpc/include/asm/qspinlock.h > @@ -31,16 +31,57 @@ static inline void queued_spin_unlock(struct qspinlock *lock) > > #else > ex...