From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Date: Mon, 16 Jan 2012 19:42:38 +0100 Message-ID: References: <20120114182501.8604.68416.sendpatchset@oc5400248562.ibm.com> <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> <20120116142014.GA10155@linux.vnet.ibm.com> <4F146EA5.3010106@linux.vnet.ibm.com> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jeremy Fitzhardinge , Greg Kroah-Hartman , linux-doc@vger.kernel.org, Peter Zijlstra , Jan Kiszka , Srivatsa Vaddagiri , Paul Mackerras , "H. Peter Anvin" , Stefano Stabellini , Xen , Dave Jiang , KVM , Glauber Costa , X86 , Ingo Molnar , Avi Kivity , Rik van Riel , Konrad Rzeszutek Wilk , Sasha Levin , Sedat Dilek , Thomas Gleixner , Virtualization , LKML , Dave Hansen Return-path: In-Reply-To: <4F146EA5.3010106@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On 16.01.2012, at 19:38, Raghavendra K T wrote: > On 01/16/2012 07:53 PM, Alexander Graf wrote: >> >> On 16.01.2012, at 15:20, Srivatsa Vaddagiri wrote: >> >>> * Alexander Graf [2012-01-16 04:57:45]: >>> >>>> Speaking of which - have you benchmarked performance degradation of pv ticket locks on bare metal? >>> >>> You mean, run kernel on bare metal with CONFIG_PARAVIRT_SPINLOCKS >>> enabled and compare how it performs with CONFIG_PARAVIRT_SPINLOCKS disabled for >>> some workload(s)? >> >> Yup >> >>> >>> In some sense, the 1x overcommitcase results posted does measure the overhead >>> of (pv-)spinlocks no? We don't see any overhead in that case for atleast >>> kernbench .. >>> >>>> Result for Non PLE machine : >>>> ============================ >>> >>> [snip] >>> >>>> Kernbench: >>>> BASE BASE+patch >> >> What is BASE really? Is BASE already with the PV spinlocks enabled? I'm having a hard time understanding which tree you're working against, since the prerequisites aren't upstream yet. >> >> >> Alex > > Sorry for confusion, I think I was little imprecise on the BASE. > > The BASE is pre 3.2.0 + Jeremy's following patches: > xadd (https://lkml.org/lkml/2011/10/4/328) > x86/ticketlocklock (https://lkml.org/lkml/2011/10/12/496). > So this would have ticketlock cleanups from Jeremy and > CONFIG_PARAVIRT_SPINLOCKS=y > > BASE+patch = pre 3.2.0 + Jeremy's above patches + above V5 PV spinlock > series and CONFIG_PARAVIRT_SPINLOCKS=y > > In both the cases CONFIG_PARAVIRT_SPINLOCKS=y. > > So let, > A. pre-3.2.0 with CONFIG_PARAVIRT_SPINLOCKS = n > B. pre-3.2.0 + Jeremy's above patches with CONFIG_PARAVIRT_SPINLOCKS = n > C. pre-3.2.0 + Jeremy's above patches with CONFIG_PARAVIRT_SPINLOCKS = y > D. pre-3.2.0 + Jeremy's above patches + V5 patches with CONFIG_PARAVIRT_SPINLOCKS = n > E. pre-3.2.0 + Jeremy's above patches + V5 patches with CONFIG_PARAVIRT_SPINLOCKS = y > > is it performance of A vs E ? (currently C vs E) Since D and E only matter with KVM in use, yes, I'm mostly interested in A, B and C :). Alex From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Date: Mon, 16 Jan 2012 19:42:38 +0100 Message-ID: References: <20120114182501.8604.68416.sendpatchset@oc5400248562.ibm.com> <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> <20120116142014.GA10155@linux.vnet.ibm.com> <4F146EA5.3010106@linux.vnet.ibm.com> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F146EA5.3010106@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Raghavendra K T Cc: Jeremy Fitzhardinge , Greg Kroah-Hartman , linux-doc@vger.kernel.org, Peter Zijlstra , Jan Kiszka , Srivatsa Vaddagiri , Paul Mackerras , "H. Peter Anvin" , Stefano Stabellini , Xen , Dave Jiang , KVM , Glauber Costa , X86 , Ingo Molnar , Avi Kivity , Rik van Riel , Konrad Rzeszutek Wilk , Sasha Levin , Sedat Dilek , Thomas Gleixner , Virtualization , LKML , Dave Hansen List-Id: virtualization@lists.linuxfoundation.org On 16.01.2012, at 19:38, Raghavendra K T wrote: > On 01/16/2012 07:53 PM, Alexander Graf wrote: >> >> On 16.01.2012, at 15:20, Srivatsa Vaddagiri wrote: >> >>> * Alexander Graf [2012-01-16 04:57:45]: >>> >>>> Speaking of which - have you benchmarked performance degradation of pv ticket locks on bare metal? >>> >>> You mean, run kernel on bare metal with CONFIG_PARAVIRT_SPINLOCKS >>> enabled and compare how it performs with CONFIG_PARAVIRT_SPINLOCKS disabled for >>> some workload(s)? >> >> Yup >> >>> >>> In some sense, the 1x overcommitcase results posted does measure the overhead >>> of (pv-)spinlocks no? We don't see any overhead in that case for atleast >>> kernbench .. >>> >>>> Result for Non PLE machine : >>>> ============================ >>> >>> [snip] >>> >>>> Kernbench: >>>> BASE BASE+patch >> >> What is BASE really? Is BASE already with the PV spinlocks enabled? I'm having a hard time understanding which tree you're working against, since the prerequisites aren't upstream yet. >> >> >> Alex > > Sorry for confusion, I think I was little imprecise on the BASE. > > The BASE is pre 3.2.0 + Jeremy's following patches: > xadd (https://lkml.org/lkml/2011/10/4/328) > x86/ticketlocklock (https://lkml.org/lkml/2011/10/12/496). > So this would have ticketlock cleanups from Jeremy and > CONFIG_PARAVIRT_SPINLOCKS=y > > BASE+patch = pre 3.2.0 + Jeremy's above patches + above V5 PV spinlock > series and CONFIG_PARAVIRT_SPINLOCKS=y > > In both the cases CONFIG_PARAVIRT_SPINLOCKS=y. > > So let, > A. pre-3.2.0 with CONFIG_PARAVIRT_SPINLOCKS = n > B. pre-3.2.0 + Jeremy's above patches with CONFIG_PARAVIRT_SPINLOCKS = n > C. pre-3.2.0 + Jeremy's above patches with CONFIG_PARAVIRT_SPINLOCKS = y > D. pre-3.2.0 + Jeremy's above patches + V5 patches with CONFIG_PARAVIRT_SPINLOCKS = n > E. pre-3.2.0 + Jeremy's above patches + V5 patches with CONFIG_PARAVIRT_SPINLOCKS = y > > is it performance of A vs E ? (currently C vs E) Since D and E only matter with KVM in use, yes, I'm mostly interested in A, B and C :). Alex