Re: [vserver] Re: How do I stop a high guest CPU load and ifb0 from dropping internet packets?

From: Fog_Watch <>
Date: Sat 17 Aug 2013 - 06:06:21 BST
Message-ID: <>

On Fri, 16 Aug 2013 13:31:49 +0200
Herbert Poetzl <> wrote:

> Okay, what kernel/patch/util-vserver version?
# vserver-info
                   Kernel: 3.9.5-vs2.3.6.5
                   VS-API: 0x00020308
                      VCI: 0x0000000013003f11
             util-vserver: 0.30.216-pre3025; Nov 15 2012, 15:10:33

                       CC: x86_64-pc-linux-gnu-gcc,
x86_64-pc-linux-gnu-gcc (Gentoo 4.5.4 p1.0, pie-0.4.7) 4.5.4 CPPFLAGS:
'' CFLAGS: '-march=native -std=c99 -Wall -pedantic -W -funit-at-a-time'
               build/host: x86_64-pc-linux-gnu/x86_64-pc-linux-gnu
             Use dietlibc: yes
       Build C++ programs:
       Build C99 programs: yes
           Available APIs: v13,net,v21,v22,v23,netv2
            ext2fs Source: e2fsprogs
    syscall(2) invocation: alternative
      vserver(2) syscall#: 236/glibc
               crypto api: beecrypt
          python bindings: no
   use library versioning: yes

                   prefix: /usr
        sysconf-Directory: /etc
            cfg-Directory: /etc/vservers
         initrd-Directory: $(sysconfdir)/init.d
       pkgstate-Directory: /var/run/vservers
          vserver-Rootdir: /vservers

> Are network related interrupts routed to the host
> only CPU (0 in your case)?
Sorry, I don't know how to do that.

net1 is my Internet interface:
# grep net1 /etc/conf.d/net

net1 uses interrupt 65:
# cat /proc/interrupts | head -n 1 && cat /proc/interrupts | grep net1
            CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
  65: 38806 36024 38935 35519 38778 35409 39808 35463 PCI-MSI-edge net1

On my eight core machine I thought that something like the following
would force CPU 0 to use interrupt 65:
# echo 01 > /proc/irq/65/smp_affinity

But maybe it doesn't because the interrupt still seems to be shared:
# cat /proc/interrupts | head -n 1 && cat /proc/interrupts | grep net1
            CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
  65: 38834 36260 38956 35737 38810 35617 39837 35678 PCI-MSI-edge net1

> Does it happen on a specific guest?
Packets are dropped when any guest is under load.

> If so, which guest load triggers it?
> > How do I prevent my guest-related packet drops?
> Ingress filtering works by dropping packets, so
> how do you know that the packets are not dropped
> because the limit was reached?
I don't know. But what I do know is that, with only pings across the interface the host maxing-out all eight
cores does not cause packet loss when ingress is filtered with intermediate functional block. Any guest using as few as one core does cause packet loss.

Thank you very much for your reply.


Received on Sat Aug 17 06:06:31 2013

[Next/Previous Months] [Main vserver Project Homepage] [Howto Subscribe/Unsubscribe] [Paul Sladen's vserver stuff]
Generated on Sat 17 Aug 2013 - 06:06:31 BST by hypermail 2.1.8