Chu, Sam
2006-Dec-11 07:16 UTC
[Xen-users] Network performance difference between x86 and x86_64 guest OS
Here is my setup Xen: 3.0.3 Xen OS: Red Hat Enterprise Linux 4 update 3. Guest OS: Red Hat Enterprise Linux4 update 3, x86_64 and x86. NIC: Broadcom NetXtreme II BCM5708 Guest OS: NIC is pcnet X86_64 network test data: ~4 MB/s (copying a 150 MB file) X86 network test data: ~6 MB/s (copying the same file) Has anyone seen this big of difference between two basically the same OS running on the same virtual machine? Sam _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Henning Sprang
2006-Dec-12 12:34 UTC
Re: [Xen-users] Network performance difference between x86 and x86_64 guest OS
On 12/11/06, Chu, Sam <sam.chu@intel.com> wrote:> [...] > X86_64 network test data: ~4 MB/s (copying a 150 MB file) > > X86 network test data: ~6 MB/s (copying the same file)There can be quite some differences. I did also not think about this before, but heard a very interesting talk from Harald Welt of the netfilter team about (high) network performance. There are a lot of factors going into network performance, and 32 vs. 64 bit makes quite some difference, but on the other side it depends also a lot on the type of data you transfer and protocols. This means: depending on your data and protocols, it is really possible that the bitness make such a big difference. Already on real hardware, and in also Xen-internals with handling this bitness make a difference. Unforunately his paper isn''t published yet (as the others from the conference are), maybe it will be available on http://www.heinlein-support.de/web/secure-linux-administration-conference/slac-downloadupdates/ some day. (most other papers are in german, but I know his paper was in english!) Henning _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users