On 11/26/14 15:48, Laszlo Ersek wrote: > Hi, > > On 11/13/14 19:42, Jordan Justen wrote: >> On 2014-11-06 17:23:01, Fan, Jeff wrote: >>> Chen, >>> >>> Thanks your contribution. I will check-in your patch if there is no >>> further comments from other guys. >>> >>> Reviewed-by: Jeff Fan <jeff....@intel.com> >> >> Chen, >> >> I committed your series (r16345-r16371) for Jeff (to preserve the >> separate patches). >> >> Thanks for all your work on this! >> >> Let me know if you are interested in working on some follow up MP >> tasks. (I have 2 ideas. :) >> >> Jeff, >> >> Thanks for your review of this big series! > > I believe this series introduces an interesting performance regression, > at least when it is part of OVMF and runs on qemu/kvm. > > Now the APs seem to be spinning infinitely, for example while the user > is in the UEFI Setup utility. Before, there used to be no CPU load to > speak of, while the user was in the UEFI Setup utility.
Of course the above holds for all other UEFI applications too, not just the setup utility. For example, the same can be experienced while working in the UEFI Shell. In a 4 VCPU guest on a 4 PCPU host, I got an idle Shell> prompt (running on the virtual BP), and 75% host CPU load, due to the three virtual APs spinning (hogging 3 PCPUs out of 4). Thanks Laszlo > The useless spinning is quite bad: > - it hogs physical CPUs on the virtualization host for no good reason, > - it wastes electricity (problem for both laptops and data centers). > > Can we make this feature dependent on a Feature PCD? At the moment I > can't think of any workload I would run on the APs during runtime. > > Thoughts? > > Thanks > Laszlo > ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
