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    XCP-ng 8.0.0 Beta now available!

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    • P
      peder last edited by

      It does NOT work to migrate a paravirtualized (PV) CentOS6 machine or a PVHVM CentOS7 between two "servers" with Core i3-3110M CPUs in 8.0beta.
      C6 throws a "xenopsd, error from emu-manager: Invalid argument" and C7 "xenopsd, error from emu-manager: xenguest Invalid argument".

      It works on the exact same hardware in 7.6 so that seems to be a new "unsupported old CPU" limitation, unless it's a proper bug in 8.0b.

      I can migrate a Fedora28 (HVM) on that hardware in 8.0b so it appears to depend on what virtualization method the machine uses.

      stormi 1 Reply Last reply Reply Quote 0
      • stormi
        stormi Vates πŸͺ XCP-ng Team πŸš€ @peder last edited by

        @peder Thanks for testing. It confirms our recent findings related to PV guests indeed! We're working on it and will post here once it's fixed.

        P 1 Reply Last reply Reply Quote 1
        • P
          peder @stormi last edited by

          @stormi Nice to hear, thanks!

          1 Reply Last reply Reply Quote 0
          • ronan-a
            ronan-a Vates πŸͺ XCP-ng Team πŸš€ last edited by ronan-a

            @peder Fixed! This fix will be available (as soon as possible) in a future xcp-emu-manager package.

            1 Reply Last reply Reply Quote 2
            • stormi
              stormi Vates πŸͺ XCP-ng Team πŸš€ last edited by

              I have updated https://github.com/xcp-ng/xcp/wiki/Test-XCP with lots of new tests for those who need ideas πŸ™‚

              1 Reply Last reply Reply Quote 0
              • s_mcleod
                s_mcleod last edited by s_mcleod

                Just FYI - I have performed CPU and PGBench benchmarks on XCP-ng 8 beta 1, both with Hyperthreading enabled and disabled when running two identical VMs under different types of low, medium and heavy CPU load.

                Results are available here: https://github.com/sammcj/benchmark_results/tree/master/xcpng/8/hyperthreading_impact

                TLDR;

                • Significant performance decrease (38.7725%) when running multithreaded Sysbench CPU benchmarks in parallel on two VMs when hyperthreading is disabled.

                • Significant performance decrease (16.96%) when running PGBench under 'normal' load benchmarks in parallel on two VMs when hyperthreading is disabled.

                • No significant performance decrease when running Phoronix Test Suite's Pybench and OpenSSL benchmarks in parallel on two VMs when hyperthreading is disabled.

                MajorTom 1 Reply Last reply Reply Quote 1
                • stormi
                  stormi Vates πŸͺ XCP-ng Team πŸš€ last edited by

                  yum update will now install the latest xcp-ng-emu-manager that fixes the PV guest migration and brings better debug traces in case of crash of the emu-manager binary. We'd be interested if anyone managed to make a migration fail.

                  Testing ideas still at https://github.com/xcp-ng/xcp/wiki/Test-XCP

                  P 1 Reply Last reply Reply Quote 1
                  • MajorTom
                    MajorTom @s_mcleod last edited by

                    @s_mcleod Hi, I'd like to do some basic benchmarks (though not on 8.0.0, but 7.6 still) to compare a host before and after disabling SMT (hyper-threading).

                    I thought I'd use some hints from your document at https://github.com/sammcj/benchmark_results/tree/master/xcpng/8/hyperthreading_impact

                    But the "Test 2 - Sysbench Multithreaded Prime Benchmark" link (https://github.com/sammcj/benchmark_results/blob/master/xcpng/8/hyperthreading_impact/hyperthreading_impact/test_2_sysbench_prime.md) returns "404 page not found".

                    Maybe you'd want to correct the link? Thank you!

                    s_mcleod 1 Reply Last reply Reply Quote 0
                    • P
                      peder @stormi last edited by

                      @stormi I just managed to make migration fail using xcp-emu-manager-1.1.1-1 and xcp-ng-generic-lib-1.1.1-1 πŸ™‚

                      I have a PVHVM guest (CentOS7) which has static memory limit = 128M/2G and dynamic = 1G/1G and the migration fails after about 20% with a "xenguest invalid argument"
                      It works if I set static and dynamic max to the same value.

                      Migration of a PVHVM Fedora 28 with static 1G/2G and dynamic 1G/1G works so it's possible it's the 128M static min that's part of the problem in the CentOS case.

                      A PV CentOS6 with static = 512M/2G and dynamic 1G/1G also works.

                      stormi 1 Reply Last reply Reply Quote 0
                      • stormi
                        stormi Vates πŸͺ XCP-ng Team πŸš€ @peder last edited by

                        @peder Thanks! Could you make it fail once again and then produce a bug status report on both hosts with xen-bugtool -y and send the the produced tarballs to the project contact address, or to upload it somewhere temporarily for us to download?

                        P 1 Reply Last reply Reply Quote 0
                        • olivierlambert
                          olivierlambert Vates πŸͺ Co-Founder🦸 CEO πŸ§‘β€πŸ’Ό last edited by

                          I just made a try here, I can't reproduce with the same guest OS and memory settings.

                          Are you also doing Xen Storage motion?

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                          • P
                            peder @stormi last edited by

                            @stormi I've placed the tarballs here https://student.oedu.se/~peder/xcp-ng/
                            I changed the static min to 512M, to match the Fedora case, but it still failed.

                            Olivier, I'm not using Xen Storage motion but I am using two old Lenovo L430 Thinkpads as "servers" so that could be part of the problem.

                            I'll install a new C7 guest and see if the problem persists.

                            1 Reply Last reply Reply Quote 1
                            • P
                              peder @olivierlambert last edited by

                              @olivierlambert The VM that fails migration seems to have been created in xcp-ng 7.6 using the "Other Media" template.
                              I made a new VM in xcp-ng 8 using the CentOS7 template and I can migrate that just fine with a larger static max.

                              1 Reply Last reply Reply Quote 0
                              • olivierlambert
                                olivierlambert Vates πŸͺ Co-Founder🦸 CEO πŸ§‘β€πŸ’Ό last edited by

                                Can you provide the full VM record of the problematic one? with

                                vm param-list uuid=<YOUR FAILING VM UUID>

                                Also the same with the one now working, so I can compare.

                                P 1 Reply Last reply Reply Quote 0
                                • P
                                  peder @olivierlambert last edited by

                                  @olivierlambert Sure.
                                  I've put the param-list logs as well as the VMs (sans the Disk) on https://student.oedu.se/~peder/xcp-ng/

                                  1 Reply Last reply Reply Quote 0
                                  • olivierlambert
                                    olivierlambert Vates πŸͺ Co-Founder🦸 CEO πŸ§‘β€πŸ’Ό last edited by

                                    So I imported your VM metadata in my lab pool, attached to a VM disk with Debian (so we don't really care about the OS) and it worked πŸ˜†

                                    I also attached a disk of a previously working CentOS 7 VM, same thing: migration worked 🐹

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                                    • P
                                      peder last edited by

                                      Weird.

                                      Maybe it's due to the hardware I'm using. I only have 8 GB RAM in the servers but the migration fails even if I'm not running any other VM.
                                      And since it works if static max=dynamic max it shouldn't be a RAM case either.

                                      Unless the migration for some reason tries to allocate 2-3 times the amount of RAM if static and dynamic max differ.

                                      1 Reply Last reply Reply Quote 0
                                      • s_mcleod
                                        s_mcleod @MajorTom last edited by

                                        @MajorTom Sorry about that I've been (and still am AFK):

                                        Corrected link: https://github.com/sammcj/benchmark_results/blob/master/xcpng/8/hyperthreading_impact/test_2_sysbench_prime.md

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                                        • A
                                          AllooTikeeChaat last edited by AllooTikeeChaat

                                          Folks... was at Citrix event today and the morning was a talk by LoginVSI looking at the impact of the latest security patches for Intel CPU's and the performance impact server on EUC work loads and server scalebility on the Hypervisors. According to the presenter all the Hypervisors (Hyper-V, VMware ESX and XenServer) that they were testing were seeing approx 20-25% decrease in performance when using Intel based systems. What I found interesting was VMware has developed a new scheduler, SCAv2 to help reduce the impact although no numbers where mentioned. There was no mention of anything of th sort for XenServer or HyperV.

                                          https://blogs.vmware.com/performance/2019/05/new-scheduler-option-for-vsphere-6-7-u2.html

                                          According to that blog post .. the impact using the SCAv2 was reduced to 11%.

                                          1 Reply Last reply Reply Quote 1
                                          • olivierlambert
                                            olivierlambert Vates πŸͺ Co-Founder🦸 CEO πŸ§‘β€πŸ’Ό last edited by

                                            This will come in Xen. In fact, work already started. It's called "core scheduling", and this is the preliminary work before sync scheduling, which is a perfect solution (better perfs AND better security) against Intel CPU flaws.

                                            Source: https://lists.xenproject.org/archives/html/xen-devel/2019-05/msg00370.html

                                            A 1 Reply Last reply Reply Quote 0
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