On Fri, Aug 06, 2021 at 12:24:36PM +0000, Shameerali Kolothum Thodi wrote: > These are some test numbers with and without this patch, run on two > different test setups. > > > a)Test Setup -1 > ----------------------- > > Platform: HiSilicon D06 with 128 CPUs, VMID bits = 16 > Run 128 VMs concurrently each with 2 vCPUs. Each Guest will execute hackbench > 5 times before exiting. > > Measurements taken avg. of 10 Runs. > > Image : 5.14-rc3 > --------------------------- > Time(s) 44.43813888 > No. of exits 145,348,264 > > Image: 5.14-rc3 + vmid-v3 > ---------------------------------------- > Time(s) 46.59789034 > No. of exits 133,587,307 > > %diff against 5.14-rc3 > Time: 4.8% more > Exits: 8% less > > Image: 5.14-rc3 + vmid-v3 + Without active_asid clear > --------------------------------------------------------------------------- > Time(s) 44.5031782 > No. of exits 144,443,188 > > %diff against 5.14-rc3 > Time: 0.15% more > Exits: 2.42% less > > b)Test Setup -2 > ----------------------- > > Platform: HiSilicon D06 + Kernel with maxcpus set to 8 and VMID bits set to 4. > Run 40 VMs concurrently each with 2 vCPUs. Each Guest will execute hackbench > 5 times before exiting. > > Measurements taken avg. of 10 Runs. > > Image : 5.14-rc3-vmid4bit > ------------------------------------ > Time(s) 46.19963266 > No. of exits 23,699,546 > > Image: 5.14-rc3-vmid4bit + vmid-v3 > --------------------------------------------------- > Time(s) 45.83307736 > No. of exits 23,260,203 > > %diff against 5.14-rc3-vmid4bit > Time: 0.8% less > Exits: 1.85% less > > Image: 5.14-rc3-vmid4bit + vmid-v3 + Without active_asid clear > ----------------------------------------------------------------------------------------- > Time(s) 44.5031782 > No. of exits 144,443,188 Really? The *exact* same numbers as the "Image: 5.14-rc3 + vmid-v3 + Without active_asid clear" configuration? Guessing a copy-paste error here. > %diff against 5.14-rc3-vmid4bit > Time: 1.05% less > Exits: 2.06% less > > As expected, the active_asid clear on schedule out is not helping. > But without this patch, the numbers seems to be better than the > vanilla kernel when we force the setup(cpus=8, vmd=4bits) > to perform rollover. I'm struggling a bit to understand these numbers. Are you saying that clearing the active_asid helps in the 16-bit VMID case but not in the 4-bit case? Why would the active_asid clear have any impact on the number of exits? The problem I see with not having the active_asid clear is that we will roll over more frequently as the number of reserved VMIDs increases. Will _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
