[Xen-devel] network performance drop heavily in xen 4.0 release

[yingbin wang <yingbin.wangyb@xxxxxxxxx>]

Hi:
    I report a Bug !!!  We have just upgraded to
xen4.0+kernel2.6.31.13 recently.  however , fond that the network
performance drop heavily in dom0  (nearly Reduced by 2/3 vs
xen3.4.2+kernel2.6.18.8 ) .

our env :
hardware :
  Intel(R) Xeon(R) CPU           E5520  @ 2.27GHz
  01:00.0 Ethernet controller: Broadcom Corporation NetXtreme II
BCM5709 Gigabit Ethernet (rev 20)
  01:00.1 Ethernet controller: Broadcom Corporation NetXtreme II
BCM5709 Gigabit Ethernet (rev 20)
compile env and filesystem :
  Redhat AS 5.4

xm info :
-----------------------------------------------------------------
host                   : r02k08015
release                : 2.6.31.13xen
version                : #1 SMP Tue Apr 13 20:38:51 CST 2010
machine                : x86_64
nr_cpus                : 16
nr_nodes               : 2
cores_per_socket       : 4
threads_per_core       : 2
cpu_mhz                : 2266
hw_caps                :
bfebfbff:28100800:00000000:00001b40:009ce3bd:00000000:00000001:00000000
virt_caps              : hvm
total_memory           : 24539
free_memory            : 15596
node_to_cpu            : node0:0,2,4,6,8,10,12,14
                        node1:1,3,5,7,9,11,13,15
node_to_memory         : node0:3589
                        node1:12007
node_to_dma32_mem      : node0:2584
                        node1:0
max_node_id            : 1
xen_major              : 4
xen_minor              : 0
xen_extra              : .0
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          : unavailable
xen_commandline        : dom0_mem=10240M
cc_compiler            : gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)
cc_compile_by          : root
cc_compile_domain      :
cc_compile_date        : Tue Apr 13 23:04:16 CST 2010
xend_config_format     : 4
---------------------------------------------------------------------------


test tool:  iperf-2.0.4
command:
root@xxxxxxxxxxx :      iperf -s
root@xxxxxxxxxxx :      iperf -c 10.250.6.25 -i 1 -t 100

network performance:

xen4.0+kernel2.6.31.13:
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0- 9.5 sec    249 MBytes    219 Mbits/sec

xen3.4.2+kernel2.6.18.8:
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-15.0 sec  1.64 GBytes    941 Mbits/sec

BTW ,1 the disk IO performance also reduce from 90MB/s to 60MB/s.
        2 the attachment is the dom0 kernel compile config.

Cheers,
wyb

config-2.6.31-13xen
Description: Binary data

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