From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srivatsa Vaddagiri Subject: Re: [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Date: Mon, 16 Jan 2012 19:50:23 +0530 Message-ID: <20120116142014.GA10155@linux.vnet.ibm.com> References: <20120114182501.8604.68416.sendpatchset@oc5400248562.ibm.com> <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> Reply-To: Srivatsa Vaddagiri Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jeremy Fitzhardinge , Raghavendra K T , linux-doc@vger.kernel.org, Peter Zijlstra , Jan Kiszka , Virtualization , Paul Mackerras , "H. Peter Anvin" , Stefano Stabellini , Xen , Dave Jiang , KVM , Glauber Costa , X86 , Ingo Molnar , Avi Kivity , Rik van Riel , Konrad Rzeszutek Wilk , Greg Kroah-Hartman , Sasha Levin , Sedat Dilek , Thomas Gleixner , LKML , Dave Hansen Return-path: Content-Disposition: inline In-Reply-To: <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> 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 * 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)? 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 > %improvement > mean (sd) mean (sd) > Scenario A: > case 1x: 164.233 (16.5506) 163.584 (15.4598 0.39517 [snip] > Result for PLE machine: > ====================== [snip] > Kernbench: > BASE BASE+patch > %improvement > mean (sd) mean (sd) > Scenario A: > case 1x: 161.263 (56.518) 159.635 (40.5621) 1.00953 - vatsa From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srivatsa Vaddagiri Subject: Re: [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Date: Mon, 16 Jan 2012 19:50:23 +0530 Message-ID: <20120116142014.GA10155@linux.vnet.ibm.com> References: <20120114182501.8604.68416.sendpatchset@oc5400248562.ibm.com> <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> Reply-To: Srivatsa Vaddagiri Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <3EC1B881-0724-49E3-B892-F40BEB07D15D@suse.de> 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: Alexander Graf Cc: Jeremy Fitzhardinge , Raghavendra K T , linux-doc@vger.kernel.org, Peter Zijlstra , Jan Kiszka , Virtualization , Paul Mackerras , "H. Peter Anvin" , Stefano Stabellini , Xen , Dave Jiang , KVM , Glauber Costa , X86 , Ingo Molnar , Avi Kivity , Rik van Riel , Konrad Rzeszutek Wilk , Greg Kroah-Hartman , Sasha Levin , Sedat Dilek , Thomas Gleixner , LKML Dave Hansen List-Id: virtualization@lists.linuxfoundation.org * 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)? 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 > %improvement > mean (sd) mean (sd) > Scenario A: > case 1x: 164.233 (16.5506) 163.584 (15.4598 0.39517 [snip] > Result for PLE machine: > ====================== [snip] > Kernbench: > BASE BASE+patch > %improvement > mean (sd) mean (sd) > Scenario A: > case 1x: 161.263 (56.518) 159.635 (40.5621) 1.00953 - vatsa