[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Xen optimization
Hello All, On 27.11.18 23:27, Stefano Stabellini wrote: See the following: https://marc.info/?l=xen-devel&m=148668817704668 So I did port that stuff to the current staging [1]. Also, the correspondent tbm, itself is here [2]. Having 4 big cores on my SoC I run XEN with the following command line: dom0_mem=3G console=dtuart dtuart=serial0 dom0_max_vcpus=2 bootscrub=0 loglvl=all cpufreq=none tbuf_size=8192 loglvl=all/none guest_loglvl=all/none The TBM's domain configuration file is as following: seclabel='system_u:system_r:domU_t' name = "DomP" kernel = "/home/root/ctest-bare.bin" extra = "console=hvc0 rw" memory = 128 vcpus = 1 cpus = "3" This gives me setup where Domain-0 runs on cores 0 and 1 solely and TBM runs exclusively on core 3. So that we can rely that it shows us a pure IRQ latency of hypervisor. My board is Renesas Salvator-X with H3 ES3.0 SoC and 8GB RAM. Generic timer runs at 8.333 MHz freq, what gives my 120ns resolution for measurements. XEN hypervisor is build without debug and TBM does wfi in the idle loop for all experiments. With that setup IRQ latency numbers are (in ns): Old vgic: AVG MIN MAX WARM MAX credit, vwfi=trap 7706 7560 9480 8400 credit, vwfi=native 2908 2880 3120 4800 credit2, vwfi=trap 7221 7200 9240 7440 credit2, vwfi=native 2906 2880 3120 5040 New vgic: AVG MIN MAX WARM MAX credit, vwfi=trap 8481 8040 10200 8880 credit, vwfi=native 4115 3960 4800 4200 credit2, vwfi=trap 8425 8400 9600 9000 credit2, vwfi=native 4227 3960 5040 4680 Here we can see that the new vgic underperforms the old one in a trivial use-case modeled with TBM. Old vgic with optimizations [3] (without [4], because it breaks the setup): AVG MIN MAX WARM MAX credit, vwfi=trap 7309 7080 8760 7680 credit, vwfi=native 3007 3000 4320 3120 credit2, vwfi=trap 6877 6720 8880 7200 credit2, vwfi=native 2680 2640 4440 2880 [1] https://github.com/aanisov/xen/tree/4tbm [2] https://github.com/aanisov/tbm/commits/4xen [3] https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03328.html [4] https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03288.html -- Sincerely, Andrii Anisov. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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