Hi guys. Maybe we are suffering some related issue. If not, feel free to
ignore this message.
I wrote on this list but none replyed:
"Fresh installed server with Debian Buster on top of nvme swRaid1 (mdadm)
Testing hdd write seed with dd (with convert=fdatasync option) gives me
the result of 330MB/s. Good.
Installed xen-system and xen-tools (with --no-recommends option in apt)
from official repository. Rebooted the system.
Re-tested hdd write seed with dd (with convert=fdatasync option) gives
me the result of 108MB/s. Not good at all.
Maybe the following is not related to the issue, but on dmesg there is a
line when I boot the system with Xen kernel:
...
[ 14.214044] Performance Events: unsupported p6 CPU model 158 no PMU
driver, software events only.
...
Instead, when I boot the system without Xen kernel I have these lines in
dmesg:
...
[ 0.517217] Performance Events: PEBS fmt3+, Skylake events, 32-deep
LBR, full-width counters, Intel PMU driver.
[ 0.517356] ... version: 4
[ 0.517444] ... bit width: 48
[ 0.517444] ... generic registers: 4
[ 0.517444] ... value mask: 0000ffffffffffff
[ 0.517444] ... max period: 00007fffffffffff
[ 0.517444] ... fixed-purpose events: 3
[ 0.517444] ... event mask: 000000070000000f
"
Personally, I moved to KVM+libvirt nearly without rework.
I/O performance are great.
But I love XEN and I will be pleased to come back to it.
g
On 03/05/20 19:24, Agustin Lopez wrote:
>
>
> Sorry. I booted with 8 GB for the Dom0 and all is the same.
>
> I have seen one difference between the 2 xl info:
>
> (AGUSTIN) virt_caps : hvm hvm_directio
>
> (OLIVIER) virt_caps : pv hvm hvm_directio pv_directio hap
> shadow iommu_hap_pt_share
>
>
> Could this be the problem?
>
>
> Agustín
>
>
> El 3/5/20 a las 18:50, Rob Townley escribió:
>> Agustin, noticed ‘ dom0_mem=2048M,max:4065M’,
>> so increasing RAM allocated to Dom0 might speed up the VMs.
>>
>> 2GB for dom0 is extremely low in my opinion especially when most of
>> the 256GB of host RAM is going to waste.
>>
>> dom0_mem=2048M,max:4065M
>>
>> On Sun, May 3, 2020 at 10:41 AM Olivier Lambert
>> <lambert.olivier@gmail.com <mailto:lambert.olivier@gmail.com>> wrote:
>>
>> Hard to tell. Here is my xl info to compare:
>>
>> host : xcp-ng-lab-3
>> release : 4.19.0+1
>> version : #1 SMP Thu Feb 13 17:34:28 CET 2020
>> machine : x86_64
>> nr_cpus : 4
>> max_cpu_id : 3
>> nr_nodes : 1
>> cores_per_socket : 4
>> threads_per_core : 1
>> cpu_mhz : 3312.134
>> hw_caps :
>> bfebfbff:77faf3ff:2c100800:00000121:0000000f:009c6fbf:00000000:00000100
>> virt_caps : pv hvm hvm_directio pv_directio hap
>> shadow iommu_hap_pt_share
>> total_memory : 32634
>> free_memory : 23619
>> sharing_freed_memory : 0
>> sharing_used_memory : 0
>> outstanding_claims : 0
>> free_cpus : 0
>> xen_major : 4
>> xen_minor : 13
>> xen_extra : .0-8.4.xcpng8.1
>> xen_version : 4.13.0-8.4.xcpng8.1
>> xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p
>> hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
>> xen_scheduler : credit
>> xen_pagesize : 4096
>> platform_params : virt_start=0xffff800000000000
>> xen_changeset : 85e1424de2dd, pq f9dbf852550e
>> xen_commandline : watchdog ucode=scan dom0_max_vcpus=1-4
>> crashkernel=256M,below=4G console=vga vga=mode-0x0311
>> dom0_mem=8192M,max:8192M
>> cc_compiler : gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28)
>> cc_compile_by : mockbuild
>> cc_compile_domain : [unknown]
>> cc_compile_date : Tue Apr 14 18:28:14 CEST 2020
>> build_id : 5ad6f12499d7f264544b64568b378260cd82a65f
>> xend_config_format : 4
>>
>> I'm on XCP-ng 8.1. Other diff is also I have more GHz than you.
>> So I ran the test on another server (building a VM just for you
>> :p ) and here is the result for a Xeon E5-2650L v2 @ 1.70GHz
>> (slow!) and VM disk stored on a NFS share.
>>
>> real 0m5,925s
>> user 0m3,769s
>> sys 0m2,321s
>>
>> Still, far better than 20 seconds you have!
>>
>> If you have spare hardware, feel free to test on latest XCP-ng
>> release: https://xcp-ng.org/docs/install.html
>>
>> Let me know if you need further help :)
>>
>>
>> Best,
>>
>> Olivier.
>>
>>
>> Le dim. 3 mai 2020 à 14:27, Agustin Lopez <Agustin.Lopez@uv.es
>> <mailto:Agustin.Lopez@uv.es>> a écrit :
>>
>> Hi Oliver.
>>
>> I am testing a bit more. In seconds, the results of the
>> command is:
>> Debian Buster PV -> 18'
>> Debian Buster HVM -> 8'
>> Debian Buster PVHVM -> 8'
>> Debian Buster PVH -> 8'
>>
>>
>> xl info
>> release : 4.19.0-8-amd64
>> version : #1 SMP Debian 4.19.98-1+deb10u1
>> (2020-04-27)
>> machine : x86_64
>> nr_cpus : 48
>> max_cpu_id : 47
>> nr_nodes : 2
>> cores_per_socket : 12
>> threads_per_core : 2
>> cpu_mhz : 2197.458
>> hw_caps :
>> bfebfbff:77fef3ff:2c100800:00000121:00000001:001cbfbb:00000000:00000100
>> virt_caps : hvm hvm_directio
>> total_memory : 261890
>> free_memory : 255453
>> sharing_freed_memory : 0
>> sharing_used_memory : 0
>> outstanding_claims : 0
>> free_cpus : 0
>> xen_major : 4
>> xen_minor : 11
>> xen_extra : .4-pre
>> xen_version : 4.11.4-pre
>> xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p
>> hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
>> xen_scheduler : credit
>> xen_pagesize : 4096
>> platform_params : virt_start=0xffff800000000000
>> xen_changeset :
>> xen_commandline : placeholder dom0_mem=2048M,max:4065M
>> cc_compiler : gcc (Debian 8.3.0-6) 8.3.0
>> cc_compile_by : pkg-xen-devel
>> cc_compile_domain : lists.alioth.debian.org
>> <http://lists.alioth.debian.org>
>> cc_compile_date : Wed Jan 8 20:16:51 UTC 2020
>> build_id : b6822aa1d8f867753b92985e5cb0e806e520a08c
>> xend_config_format : 4
>>
>> Oliver, I got > double values than you. Where is the problem?
>>
>> Regards,
>>
>> Agustín
>>
>>
>>
>> El 2/5/20 a las 19:56, Olivier Lambert escribió:
>>> Hi Agustin,
>>>
>>> I just did a test on XCP-ng 8.1 (Xen 4.13) with a fresh
>>> Debian 10 VM, and here is the result I have:
>>>
>>> ```
>>> # time for i in `dpkg -L ncurses-term | sort`; do if [ -f
>>> "$i" ]; then ls -ld "$i"; fi; done | tr -s " "| cut -d" "
>>> -f5,9 >/dev/null
>>>
>>> real 0m2,741s
>>> user 0m2,248s
>>> sys 0m0,574s
>>> ```
>>>
>>> My hardware isn't ultra modern: Xeon(R) CPU E3-1225 v5
>>> (3.3Ghz) on a small Dell T30 machine, VM storage on local
>>> HDD. I did the test 3 times, and I have always results
>>> between 2,6 and 2,8 secs.
>>>
>>> Regards,
>>>
>>> Olivier.
>>>
>>> Le sam. 2 mai 2020 à 18:33, Agustin Lopez
>>> <Agustin.Lopez@uv.es <mailto:Agustin.Lopez@uv.es>> a écrit :
>>>
>>> Hello.
>>>
>>>
>>> We are testing low performance in IO with the next
>>> command in Debian Buster (kernel 4.19.0-8-amd64) with
>>> Xen (4.11.4-pre)
>>>
>>> time for i in `dpkg -L ncurses-term | sort`; do
>>> if [ -f "$i" ]; then ls -ld "$i"; fi; done | tr -s " "|
>>> cut -d" " -f5,9 >/dev/null
>>>
>>>
>>> In all our Dom0s - DomUs we are getting around 20 seconds.
>>>
>>> In the same physical machines booting with Debian
>>> without Xen, we get 5-7 seconds
>>>
>>> In some KVM VMs in other server we are geting almost the
>>> same as physical.
>>>
>>> (all in local Disks. XFS filesystems. Images of DomUs in
>>> raw format)
>>>
>>>
>>> I have booted Xen with 4.8 y 4.4 releases with almost
>>> the same bad data.
>>>
>>>
>>> Where could be the problem?
>>>
>>> I think of is not normal this difference between DomUs
>>> and physical machine.
>>>
>>>
>>> Every pointer will be welcomed.
>>>
>>>
>>> Best regards,
>>>
>>> Agustín
>>>
>>>
>>>
>>>
>>>