search for: bytelocks

...ork in HVM? I saw Yes. > that in RHEL7, PV spinlock was explicitly disabled when in HVM mode. > However, this piece of code isn't in upstream code. So I wonder if > there is problem with that. The PV ticketlock fixed it for HVM. It was disabled before because the PV guests were using bytelocks while the HVM were using ticketlocks and you couldnt' swap in PV bytelocks for ticketlocks during startup. > > -Longman

...ork in HVM? I saw Yes. > that in RHEL7, PV spinlock was explicitly disabled when in HVM mode. > However, this piece of code isn't in upstream code. So I wonder if > there is problem with that. The PV ticketlock fixed it for HVM. It was disabled before because the PV guests were using bytelocks while the HVM were using ticketlocks and you couldnt' swap in PV bytelocks for ticketlocks during startup. > > -Longman

On Wed, Mar 25, 2015 at 03:47:39PM -0400, Konrad Rzeszutek Wilk wrote: > Ah nice. That could be spun out as a seperate patch to optimize the existing > ticket locks I presume. Yes I suppose we can do something similar for the ticket and patch in the right increment. We'd need to restructure the code a bit, but its not fundamentally impossible. We could equally apply the head hashing to

On Wed, Mar 25, 2015 at 03:47:39PM -0400, Konrad Rzeszutek Wilk wrote: > Ah nice. That could be spun out as a seperate patch to optimize the existing > ticket locks I presume. Yes I suppose we can do something similar for the ticket and patch in the right increment. We'd need to restructure the code a bit, but its not fundamentally impossible. We could equally apply the head hashing to

...citly disabled when in HVM mode. > >>>>However, this piece of code isn't in upstream code. So I wonder if > >>>>there is problem with that. > >>>The PV ticketlock fixed it for HVM. It was disabled before because > >>>the PV guests were using bytelocks while the HVM were using ticketlocks > >>>and you couldnt' swap in PV bytelocks for ticketlocks during startup. > >>The RHEL7 code has used PV ticketlock already. RHEL7 uses a single > >>kernel for all configurations. So PV ticketlock as well as Xen and > >&g...

...citly disabled when in HVM mode. > >>>>However, this piece of code isn't in upstream code. So I wonder if > >>>>there is problem with that. > >>>The PV ticketlock fixed it for HVM. It was disabled before because > >>>the PV guests were using bytelocks while the HVM were using ticketlocks > >>>and you couldnt' swap in PV bytelocks for ticketlocks during startup. > >>The RHEL7 code has used PV ticketlock already. RHEL7 uses a single > >>kernel for all configurations. So PV ticketlock as well as Xen and > >&g...

...echanism you just use the byte spinlock - which is good. And switching to PV ticketlock implementation after boot.. ugh. I feel your pain. What if you used an PV bytelock implemenation? The code you posted already 'sprays' all the vCPUS to wake up. And that is exactly what you need for PV bytelocks - well, you only need to wake up the vCPUS that have gone to sleep waiting on an specific 'struct spinlock' and just stash those in an per-cpu area. The old Xen spinlock code (Before 3.11?) had this. Just an idea thought.

...echanism you just use the byte spinlock - which is good. And switching to PV ticketlock implementation after boot.. ugh. I feel your pain. What if you used an PV bytelock implemenation? The code you posted already 'sprays' all the vCPUS to wake up. And that is exactly what you need for PV bytelocks - well, you only need to wake up the vCPUS that have gone to sleep waiting on an specific 'struct spinlock' and just stash those in an per-cpu area. The old Xen spinlock code (Before 3.11?) had this. Just an idea thought.

...s. >> that in RHEL7, PV spinlock was explicitly disabled when in HVM mode. >> However, this piece of code isn't in upstream code. So I wonder if >> there is problem with that. > The PV ticketlock fixed it for HVM. It was disabled before because > the PV guests were using bytelocks while the HVM were using ticketlocks > and you couldnt' swap in PV bytelocks for ticketlocks during startup. The RHEL7 code has used PV ticketlock already. RHEL7 uses a single kernel for all configurations. So PV ticketlock as well as Xen and KVM support was compiled in. I think booting t...

On Wed, Jun 18, 2014 at 01:37:45PM +0200, Paolo Bonzini wrote: > Il 17/06/2014 22:55, Konrad Rzeszutek Wilk ha scritto: > >On Sun, Jun 15, 2014 at 02:47:01PM +0200, Peter Zijlstra wrote: > >>From: Waiman Long <Waiman.Long at hp.com> > >> > >>This patch extracts the logic for the exchange of new and previous tail > >>code words into a new

On Wed, Jun 18, 2014 at 01:37:45PM +0200, Paolo Bonzini wrote: > Il 17/06/2014 22:55, Konrad Rzeszutek Wilk ha scritto: > >On Sun, Jun 15, 2014 at 02:47:01PM +0200, Peter Zijlstra wrote: > >>From: Waiman Long <Waiman.Long at hp.com> > >> > >>This patch extracts the logic for the exchange of new and previous tail > >>code words into a new

...inlock was explicitly disabled when in HVM mode. >>>> However, this piece of code isn't in upstream code. So I wonder if >>>> there is problem with that. >>> The PV ticketlock fixed it for HVM. It was disabled before because >>> the PV guests were using bytelocks while the HVM were using ticketlocks >>> and you couldnt' swap in PV bytelocks for ticketlocks during startup. >> The RHEL7 code has used PV ticketlock already. RHEL7 uses a single >> kernel for all configurations. So PV ticketlock as well as Xen and >> KVM support wa...

On 04/02/2014 10:32 AM, Konrad Rzeszutek Wilk wrote: > On Wed, Apr 02, 2014 at 09:27:29AM -0400, Waiman Long wrote: >> 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

On 04/02/2014 10:32 AM, Konrad Rzeszutek Wilk wrote: > On Wed, Apr 02, 2014 at 09:27:29AM -0400, Waiman Long wrote: >> 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

On Sun, Jun 15, 2014 at 02:47:07PM +0200, Peter Zijlstra wrote: > Add minimal paravirt support. > > The code aims for minimal impact on the native case. Woot! > > On the lock side we add one jump label (asm_goto) and 4 paravirt > callee saved calls that default to NOPs. The only effects are the > extra NOPs and some pointless MOVs to accomodate the calling > convention.

On Sun, Jun 15, 2014 at 02:47:07PM +0200, Peter Zijlstra wrote: > Add minimal paravirt support. > > The code aims for minimal impact on the native case. Woot! > > On the lock side we add one jump label (asm_goto) and 4 paravirt > callee saved calls that default to NOPs. The only effects are the > extra NOPs and some pointless MOVs to accomodate the calling > convention.

On 06/18/2014 09:50 AM, Konrad Rzeszutek Wilk wrote: > On Wed, Jun 18, 2014 at 01:37:45PM +0200, Paolo Bonzini wrote: >> Il 17/06/2014 22:55, Konrad Rzeszutek Wilk ha scritto: >>> On Sun, Jun 15, 2014 at 02:47:01PM +0200, Peter Zijlstra wrote: >>>> From: Waiman Long<Waiman.Long at hp.com> >>>> >>>> This patch extracts the logic for the

On Mon, Mar 17, 2014 at 01:44:34PM -0400, Waiman Long wrote: > On 03/14/2014 04:30 AM, Peter Zijlstra wrote: > >On Thu, Mar 13, 2014 at 04:05:19PM -0400, Waiman Long wrote: > >>On 03/13/2014 11:15 AM, Peter Zijlstra wrote: > >>>On Wed, Mar 12, 2014 at 02:54:52PM -0400, Waiman Long wrote: > >>>>+static inline void arch_spin_lock(struct qspinlock *lock)

On Mon, Mar 17, 2014 at 01:44:34PM -0400, Waiman Long wrote: > On 03/14/2014 04:30 AM, Peter Zijlstra wrote: > >On Thu, Mar 13, 2014 at 04:05:19PM -0400, Waiman Long wrote: > >>On 03/13/2014 11:15 AM, Peter Zijlstra wrote: > >>>On Wed, Mar 12, 2014 at 02:54:52PM -0400, Waiman Long wrote: > >>>>+static inline void arch_spin_lock(struct qspinlock *lock)

...in RHEL7, PV spinlock was explicitly disabled when in HVM mode. > >>However, this piece of code isn't in upstream code. So I wonder if > >>there is problem with that. > >The PV ticketlock fixed it for HVM. It was disabled before because > >the PV guests were using bytelocks while the HVM were using ticketlocks > >and you couldnt' swap in PV bytelocks for ticketlocks during startup. > > The RHEL7 code has used PV ticketlock already. RHEL7 uses a single > kernel for all configurations. So PV ticketlock as well as Xen and > KVM support was compiled...