search for: slowerpath

...gt; >> > > I forgot to mention - that was the crux of my comments - just change > > the slowpath to complex name at that point to better reflect what > > it does. > > Actually in my v11 patch, I subdivided the slowpath into a slowpath for > the pending code and slowerpath for actual queuing. Perhaps, we could > use quickpath and slowpath instead. Anyway, it is a minor detail that we > can discuss after the core code get merged. > > -Longman Why not do it the right way the first time around? That aside - these optimization - seem to make the code hard...

...gt; >> > > I forgot to mention - that was the crux of my comments - just change > > the slowpath to complex name at that point to better reflect what > > it does. > > Actually in my v11 patch, I subdivided the slowpath into a slowpath for > the pending code and slowerpath for actual queuing. Perhaps, we could > use quickpath and slowpath instead. Anyway, it is a minor detail that we > can discuss after the core code get merged. > > -Longman Why not do it the right way the first time around? That aside - these optimization - seem to make the code hard...

...> (*,0,0) ---> (*,0,1) -' : > * queue : ^--' : > * > + * The pending bit processing is in the trylock_pending() function whereas > + * the uncontended and contended queue processing is in the > + * queue_spin_lock_slowerpath() function. > + * > * This slowpath only contains the faster pending bit and trylock codes. > * The slower queuing code is in the slowerpath function. > */ > @@ -845,7 +844,7 @@ void queue_spin_lock_slowpath(struct qspinlock *lock, u32 val) > > BUILD_BUG_ON(CONFIG_NR_...

On 04/18/2014 05:40 PM, Waiman Long wrote: > On 04/18/2014 03:05 PM, Peter Zijlstra wrote: >> On Fri, Apr 18, 2014 at 01:52:50PM -0400, Waiman Long wrote: >>> I am confused by your notation. >> Nah, I think I was confused :-) Make the 1 _Q_LOCKED_VAL though, as >> that's the proper constant to use. > > Everyone gets confused once in a while:-) I have plenty

On 04/18/2014 05:40 PM, Waiman Long wrote: > On 04/18/2014 03:05 PM, Peter Zijlstra wrote: >> On Fri, Apr 18, 2014 at 01:52:50PM -0400, Waiman Long wrote: >>> I am confused by your notation. >> Nah, I think I was confused :-) Make the 1 _Q_LOCKED_VAL though, as >> that's the proper constant to use. > > Everyone gets confused once in a while:-) I have plenty

On Tue, Jun 17, 2014 at 04:51:57PM -0400, Waiman Long wrote: > On 06/17/2014 04:36 PM, Konrad Rzeszutek Wilk wrote: > >On Sun, Jun 15, 2014 at 02:47:00PM +0200, Peter Zijlstra wrote: > >>Because the qspinlock needs to touch a second cacheline; add a pending > >>bit and allow a single in-word spinner before we punt to the second > >>cacheline. > >Could you

On Tue, Jun 17, 2014 at 04:51:57PM -0400, Waiman Long wrote: > On 06/17/2014 04:36 PM, Konrad Rzeszutek Wilk wrote: > >On Sun, Jun 15, 2014 at 02:47:00PM +0200, Peter Zijlstra wrote: > >>Because the qspinlock needs to touch a second cacheline; add a pending > >>bit and allow a single in-word spinner before we punt to the second > >>cacheline. > >Could you

...nge of tail code word qspinlock: prolong the stay in the pending bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinlock: Add qspinlock para-virtualization support pvqspinlock, x86: Enable PV qspinlock PV for KVM pvqspinlock, x86: Enab...

...nge of tail code word qspinlock: prolong the stay in the pending bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinlock: Add qspinlock para-virtualization support pvqspinlock, x86: Enable PV qspinlock PV for KVM pvqspinlock, x86: Enab...

...bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Make a new qnode structure to support virtualization qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath unfair qspinlock: Variable frequency lock stealing mechanism unfair qspinlock: Enable lock stealing in lock waiters pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinloc...

...bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Make a new qnode structure to support virtualization qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath unfair qspinlock: Variable frequency lock stealing mechanism unfair qspinlock: Enable lock stealing in lock waiters pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinloc...

...bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Make a new qnode structure to support virtualization qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath unfair qspinlock: Variable frequency lock stealing mechanism unfair qspinlock: Enable lock stealing in lock waiters pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinloc...

...bit path qspinlock: Use a simple write to grab the lock, if applicable qspinlock: Make a new qnode structure to support virtualization qspinlock: Prepare for unfair lock support qspinlock, x86: Allow unfair spinlock in a virtual guest qspinlock: Split the MCS queuing code into a separate slowerpath unfair qspinlock: Variable frequency lock stealing mechanism unfair qspinlock: Enable lock stealing in lock waiters pvqspinlock, x86: Rename paravirt_ticketlocks_enabled pvqspinlock, x86: Add PV data structure & methods pvqspinlock: Enable coexistence with the unfair lock pvqspinloc...

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 frequency depending on its distance from the queue head. - Add performance data for IvyBridge-EX CPU.

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 frequency depending on its distance from the queue head. - Add performance data for IvyBridge-EX CPU.

N.B. Sorry for the duplicate. This patch series were resent as the original one was rejected by the vger.kernel.org list server due to long header. There is no change in content. 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

N.B. Sorry for the duplicate. This patch series were resent as the original one was rejected by the vger.kernel.org list server due to long header. There is no change in content. 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