RE: [Xen-devel] open/stat64 syscalls run faster on Xen VM than standard Linux

["Petersson, Mats" <mats.petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> xuehai zhang
> Sent: 28 November 2005 08:21
> To: Xen Mailing List
> Subject: [Xen-devel] open/stat64 syscalls run faster on Xen 
> VM than standard Linux
> 
> Dear all,
> When I debugged the execution performance of an application 
> using strace, I found there are some system calls like open 
> and stat64 which run faster on XenLinux than the standard 
> Linux. The following is the output of running "strace -c 
> /bin/sh -c /bin/echo foo" on both systems. An open call runs 
> averagely 109 usec on standard Linux but only 41 usecs on 
> XenLinux. An stat64 call runs
> 75 usecs on standard Linux but only 19 usecs on XenLinux.
> The Xen VM runs on the same physical machine as the standard 
> Linux. It uses loopback files in dom0 as the backends of VBDs.
> Any insight is highly appreciated.

And are you using the same Loopback file-system when running native
Linux? If not, it's probably the main cause of the difference. 

--
Mats

> Thanks.
> Xuehai
> 
[snip of tables]


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