Re: Bad performance with Xen

[Agustin Lopez <Agustin.Lopez@xxxxx>]

    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
    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@xxxxx> 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