search for: pvspinlock

...hed(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2.2) | 1713.7 (1.9) | 16.6 | | 848.6 (4.3) | 967.8 (4.3) | 14.0 | | 652.9 (3.5) | 685.3 (3.7) | 5.0 | +-----------------+----------------+--------+ pvspinlock shows benefits for overcommit ratio > 1 for PLE enabled cases, and undercommits results are flat. non PLE results are much better for smaller VMs. http://lkml.indiana.edu/hypermail/linux/kernel/1306.3/01095.html I would thanks all the experts here for their time in reviewing and commenting on...

...hed(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2.2) | 1713.7 (1.9) | 16.6 | | 848.6 (4.3) | 967.8 (4.3) | 14.0 | | 652.9 (3.5) | 685.3 (3.7) | 5.0 | +-----------------+----------------+--------+ pvspinlock shows benefits for overcommit ratio > 1 for PLE enabled cases, and undercommits results are flat. non PLE results are much better for smaller VMs. http://lkml.indiana.edu/hypermail/linux/kernel/1306.3/01095.html I would thanks all the experts here for their time in reviewing and commenting on...

...hed(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2.2) | 1713.7 (1.9) | 16.6 | | 848.6 (4.3) | 967.8 (4.3) | 14.0 | | 652.9 (3.5) | 685.3 (3.7) | 5.0 | +-----------------+----------------+--------+ pvspinlock shows benefits for overcommit ratio > 1 for PLE enabled cases, and undercommits results are flat. non PLE results are much better for smaller VMs. http://lkml.indiana.edu/hypermail/linux/kernel/1306.3/01095.html I would thanks all the experts here for their time in reviewing and commenting on...

...ases. Still allowing lock stealing in the fastpath is already much simpler than what my original patch was doing with lock stealing in the slowpath. If you still think it is too complex, I am willing to take that out if it is what I need to get your approval. Please also review the rests of the pvspinlock patches and let me know if you have other comments. I would like to have one more version to go and be done with it. Thanks, Longman

Shortly after I sent the first email, we found that there is another way to achieve this kind of communication, via KVM Hypercalls, I think they are underutilised in kvm, but they exist. We also found that they are architecture dependent, but the advantage is that one doesn't need to create QEMU<-> kvm interface So from our point of view it is either have things easily compatible with

> Raghavendra KT had done some performance testing on this patch with > the following results: > > Overall we are seeing good improvement for pv-unfair version. > > System: 32 cpu sandybridge with HT on (4 node with 32 GB each) > Guest : 8GB with 16 vcpu/VM. > Average was taken over 8-10 data points. > > Base = 3.15-rc2 with PRAVIRT_SPINLOCK = y > > A =

> Raghavendra KT had done some performance testing on this patch with > the following results: > > Overall we are seeing good improvement for pv-unfair version. > > System: 32 cpu sandybridge with HT on (4 node with 32 GB each) > Guest : 8GB with 16 vcpu/VM. > Average was taken over 8-10 data points. > > Base = 3.15-rc2 with PRAVIRT_SPINLOCK = y > > A =

On Wed, Jun 11, 2014 at 09:37:55PM -0400, Long, Wai Man wrote: > > On 6/11/2014 6:54 AM, Peter Zijlstra wrote: > >On Fri, May 30, 2014 at 11:43:55AM -0400, Waiman Long wrote: > >>Enabling this configuration feature causes a slight decrease the > >>performance of an uncontended lock-unlock operation by about 1-2% > >>mainly due to the use of a static key.

On Wed, Jun 11, 2014 at 09:37:55PM -0400, Long, Wai Man wrote: > > On 6/11/2014 6:54 AM, Peter Zijlstra wrote: > >On Fri, May 30, 2014 at 11:43:55AM -0400, Waiman Long wrote: > >>Enabling this configuration feature causes a slight decrease the > >>performance of an uncontended lock-unlock operation by about 1-2% > >>mainly due to the use of a static key.

Hi, I have a Windows 7 SP1 Pro 64-bit VM which works fine on libvirt 2.3.0 and Qemu 2.7.0. If I enable HyperV features (https://libvirt.org/formatdomain.html#elementsFeatures) like "relaxed", "spinlocks" etc - VM doesn't boot. "Starting Windows" text appears for ~2 seconds (no flying dots, no logo) and then it just goes to black screen. If I switch HyperV

...ll be sending a separate patchset for KVM host based on kvm tree. Please note I have added the below performance result (as suggested by HPA) in the commit log of the first patch Results: ======= setup: 32 core machine with 32 vcpu KVM guest (HT off) with 8GB RAM base = 3.11-rc patched = base + pvspinlock V12 +-----------------+----------------+--------+ dbench (Throughput in MB/sec. Higher is better) +-----------------+----------------+--------+ | base (stdev %)|patched(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2...

...ll be sending a separate patchset for KVM host based on kvm tree. Please note I have added the below performance result (as suggested by HPA) in the commit log of the first patch Results: ======= setup: 32 core machine with 32 vcpu KVM guest (HT off) with 8GB RAM base = 3.11-rc patched = base + pvspinlock V12 +-----------------+----------------+--------+ dbench (Throughput in MB/sec. Higher is better) +-----------------+----------------+--------+ | base (stdev %)|patched(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2...

...ll be sending a separate patchset for KVM host based on kvm tree. Please note I have added the below performance result (as suggested by HPA) in the commit log of the first patch Results: ======= setup: 32 core machine with 32 vcpu KVM guest (HT off) with 8GB RAM base = 3.11-rc patched = base + pvspinlock V12 +-----------------+----------------+--------+ dbench (Throughput in MB/sec. Higher is better) +-----------------+----------------+--------+ | base (stdev %)|patched(stdev%) | %gain | +-----------------+----------------+--------+ | 15035.3 (0.3) |15150.0 (0.6) | 0.8 | | 1470.0 (2...

...des implementation for both Xen and KVM. Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...des implementation for both Xen and KVM. Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...des implementation for both Xen and KVM. Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...g and correct spacing in patches 17, 18 Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...g and correct spacing in patches 17, 18 Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...g and correct spacing in patches 17, 18 Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...

...g and correct spacing in patches 17, 18 Changes in V9: - Changed spin_threshold to 32k to avoid excess halt exits that are causing undercommit degradation (after PLE handler improvement). - Added kvm_irq_delivery_to_apic (suggested by Gleb) - Optimized halt exit path to use PLE handler V8 of PVspinlock was posted last year. After Avi's suggestions to look at PLE handler's improvements, various optimizations in PLE handling have been tried. With this series we see that we could get little more improvements on top of that. Ticket locks have an inherent problem in a virtualized case, beca...