Michel Desconnets
2007-Nov-12 19:52 UTC
[Xen-users] Problem of slowness network when Nash is killed
(sorry for my english)
I have a strange problem :
I use for my dom0 the kernel of dom0
On my DomU (all is redhat 4.3), Process nash-hotplug take 99% CPU.
I have already see in mail archives that i can kill this process.
Indeed, is a good soluce, but It have big consequence : Network become
very slow !
In an other machine on network, i use a ping flood and i look performance.
When nash is running, i observe 200-300 ko/s.
If i kill bash (or just STOP it with a kill -STOP), i have 40-50 ko/s
maximum (if i restart nash with kill -CONT, i have again 300ko/s !)
I try to make a new initrd in domU : i don''t have nash any more, but
network is slow every time.
I notice that if i use vcpus > 1 in domU, network is slow every time.
with vpcus=1 and nash running : all is ok (except cpu load)
I have 2 others servers, exactly the same, but without several bridge
(just one), upgrade ok for centos 5, and network stay quick when i kill
nash: it is a coincidence, or a bug is already fixed ?
DomU : redhat 4.3, 64bit
ex :
kernel = ''/boot/vmlinuz-2.6.18-8.1.4.el5xen''
ramdisk = ''/boot/initrd-2.6.18-8.1.4.el5xen-domU.img''
memory = ''750''
root =''LABEL=xenpiraatsda1''
disk = [''phy:/dev/rootvg/xen_piraat_sda1,sda1,w'']
cpus = "1-3"
vcpus = 1
# Hostname
name = ''piraat''
# Networking
dhcp = ''dhcp''
vif = [ ''mac=00:16:3E:2F:18:F7, bridge=xenbr0'' ]
# Behaviour
on_poweroff = ''destroy''
on_reboot = ''restart''
on_crash = ''restart''
Dom0 :
CentOS release 5 (Final) 64bit, 16Go de RAM
Linux helicon 2.6.18-8.1.4.el5xen #1 SMP Thu May 17 03:43:13 EDT 2007
x86_64 x86_64 x86_64 GNU/Linux
xen-3.0.3-25.0.4.el5
2 bridges for network (1 per vlan) :
# !/bin/sh
# network-xen-multi-bridge
# Exit if anything goes wrong
set -e
# First arg is operation.
OP=$1
shift
script=/etc/xen/scripts/network-bridge.xen
case ${OP} in
start)
$script start vifnum=1 bridge=xenbr1 netdev=eth1
$script start vifnum=0 bridge=xenbr0 netdev=eth0
;;
stop)
$script stop vifnum=1 bridge=xenbr1 netdev=eth1
$script stop vifnum=0 bridge=xenbr0 netdev=eth0
;;
status)
$script status vifnum=1 bridge=xenbr1 netdev=eth1
$script status vifnum=0 bridge=xenbr0 netdev=eth0
;;
*)
echo ''Unknown command: '' ${OP}
echo ''Valid commands are: start, stop, status''
exit 1
esac
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Michel Desconnets
2007-Nov-13 19:46 UTC
[Xen-users] Problem of slowness network when Nash is killed
(sorry for my english)
I have a strange problem :
I use for my dom0 the kernel of dom0
On my DomU (all is redhat 4.3), Process nash-hotplug take 99% CPU.
I have already see in mail archives that i can kill this process.
Indeed, is a good soluce, but It have big consequence : Network become
very slow !
In an other machine on network, i use a ping flood and i look performance.
When nash is running, i observe 200-300 ko/s.
If i kill nash (or just STOP it with a kill -STOP), i have 40-50 ko/s
maximum (if i restart nash with kill -CONT, i have again 300ko/s !)
I try to make a new initrd in domU : i don''t have nash any more, but
network is slow every time.
I notice that if i use vcpus > 1 in domU, network is slow every time.
with vpcus=1 and nash running : all is ok (except cpu load)
I have 2 others servers, exactly the same, but without several bridge
(just one), upgrade ok for centos 5, and network stay quick when i kill
nash: it is a coincidence, or a bug is already fixed ?
DomU : redhat 4.3, 64bit
ex :
kernel = ''/boot/vmlinuz-2.6.18-8.1.4.el5xen''
ramdisk = ''/boot/initrd-2.6.18-8.1.4.el5xen-domU.img''
memory = ''750''
root =''LABEL=xenpiraatsda1''
disk = [''phy:/dev/rootvg/xen_piraat_sda1,sda1,w'']
cpus = "1-3"
vcpus = 1
# Hostname
name = ''piraat''
# Networking
dhcp = ''dhcp''
vif = [ ''mac=00:16:3E:2F:18:F7, bridge=xenbr0'' ]
# Behaviour
on_poweroff = ''destroy''
on_reboot = ''restart''
on_crash = ''restart''
Dom0 :
CentOS release 5 (Final) 64bit, 16Go de RAM
Linux helicon 2.6.18-8.1.4.el5xen #1 SMP Thu May 17 03:43:13 EDT 2007
x86_64 x86_64 x86_64 GNU/Linux
xen-3.0.3-25.0.4.el5
2 bridges for network (1 per vlan) :
# !/bin/sh
# network-xen-multi-bridge
# Exit if anything goes wrong
set -e
# First arg is operation.
OP=$1
shift
script=/etc/xen/scripts/network-bridge.xen
case ${OP} in
start)
$script start vifnum=1 bridge=xenbr1 netdev=eth1
$script start vifnum=0 bridge=xenbr0 netdev=eth0
;;
stop)
$script stop vifnum=1 bridge=xenbr1 netdev=eth1
$script stop vifnum=0 bridge=xenbr0 netdev=eth0
;;
status)
$script status vifnum=1 bridge=xenbr1 netdev=eth1
$script status vifnum=0 bridge=xenbr0 netdev=eth0
;;
*)
echo ''Unknown command: '' ${OP}
echo ''Valid commands are: start, stop, status''
exit 1
esac
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