On Mon, May 27, 2013 at 10:20:12AM +0800, Xiao Guangrong wrote: > On 05/25/2013 04:34 AM, Marcelo Tosatti wrote: > > On Thu, May 23, 2013 at 03:55:53AM +0800, Xiao Guangrong wrote: > >> Zap at lease 10 pages before releasing mmu-lock to reduce the overload > >> caused by requiring lock > >> > >> After the patch, kvm_zap_obsolete_pages can forward progress anyway, > >> so update the comments > >> > >> [ It improves kernel building 0.6% ~ 1% ] > > > > Can you please describe the overload in more detail? Under what scenario > > is kernel building improved? > > Yes. > > The scenario is we do kernel building, meanwhile, repeatedly read PCI rom > every one second. > > [ > echo 1 > /sys/bus/pci/devices/0000\:00\:03.0/rom > cat /sys/bus/pci/devices/0000\:00\:03.0/rom > /dev/null > ]
Can't see why it reflects real world scenario (or a real world scenario with same characteristics regarding kvm_mmu_zap_all vs faults)? Point is, it would be good to understand why this change is improving performance? What are these cases where breaking out of kvm_mmu_zap_all due to either (need_resched || spin_needbreak) on zapped < 10 ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
