From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 4/5] KVM: Add hypercall queue for paravirt_ops implementation Date: Mon, 18 Jun 2007 15:50:32 +0300 Message-ID: <46767F98.70109@qumranet.com> References: <4675F462.1010708@codemonkey.ws> <4675F568.90608@codemonkey.ws> <46764B47.5060403@qumranet.com> <46767D47.1010104@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <46767D47.1010104-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Anthony Liguori Cc: kvm-devel , virtualization List-Id: virtualization@lists.linuxfoundation.org Anthony Liguori wrote: > Avi Kivity wrote: >> Anthony Liguori wrote: >> >>> Implemented a hypercall queue that can be used when paravirt_ops >>> lazy mode >>> is enabled. This patch enables queueing of MMU write operations and CR >>> updates. This results in about a 50% bump in kernbench performance. >>> >> >> Nice! But 50%? a kernel build is at native-25%, so we're now 25% >> faster than native? > > Well, I haven't measured KVM to be 25% of native with kernbench :-) > On my LS21 (AMD), I get: I did, but using kbuild (a simple 'make' with defconfig), not kernbench. I get (elapsed time) 308 sec for kvm and 243 sec for native. Intel however is much faster than AMD due to the recent optimizations, and I guess we get some pagetable thrashing with kernbench vs. kbuild. > > KVM > Elapsed Time 1054.39 (25.8237) > User Time 371.844 (8.57204) > System Time 682.61 (17.7778) > Percent CPU 99.8 (0.447214) Sleeps 50115 (475.693) > > KVM PV > Elapsed Time 595.85 (13.7058) > User Time 360.99 (9.56093) > System Time 234.704 (4.21283) > Percent CPU 99 (0) > Context Switches 46989.8 (328.277) > Sleep 47882.8 (242.583) > > NATIVE > Elapsed Time 328.602 (0.212415) > User Time 304.364 (0.353171) > System Time 23.99 (0.325192) > Percent CPU 99 (0) > Context Switches 39785.2 (159.796) > Sleeps 46398.6 (311.466) > > With Intel, we're still only about 60% of native to start out with. > The PV patches take us to about 72%. > These numbers are pretty bad. I'd like to improve them, even without PV. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/