Re: [Xen-users] Dom0 vs native performance: does it look right?

[Ravikesh Chandra <rcha108@xxxxxxxxxxxxxxxxx>]

Thanks for your input Peter, Tom, Stefan.

Regarding TLS well, is there any way to easily verify it is the
culprit? Reading the Wiki + mailing list searches seem to imply that I
have already disabled this? (with /etc/ld.so.conf.d/xen.conf file
containing "hwcap 0 nosegneg" as reported
http://www.xen-support.com/?p=180)

Here is my output from ldconfig -v (ref
http://www.mail-archive.com/fedora-xen@xxxxxxxxxx/msg00041.html c.f.
XenFAQ)

# ldconfig -v -p 2>&1 | grep libc.so
        libc.so.6 (libc6,x86-64, OS ABI: Linux 2.6.9) => /lib64/libc.so.6
        libc.so.6 (libc6, hwcap: 0x0018000000000000, OS ABI: Linux
2.6.9) => /lib/i686/nosegneg/libc.so.6
        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6

That looks OK to me?

Cheers


2009/4/13 Peter Booth <peter_booth@xxxxxxx>:
> If you look at the wikipedia page for xen it suggests that the performance
> cost of enabling vanilla tls is 50%.
>
> It's worth trying the tls disabled configuration and seeing if this changes
> things
>
>
>
> On Apr 12, 2009, at 6:51 PM, Ravikesh Chandra <rcha108@xxxxxxxxxxxxxxxxx>
> wrote:
>
>> Hi Stefan,
>>
>> Thanks for your reply. However could you please elaborate further on
>> your statement?
>>
>> I have the file
>> "/etc/ld.so.conf.d/kernelcap-2.6.18-128.1.6.el5xen.conf" which
>> contains "hwcap 0 nosegneg".. is that what you mean? I am running a
>> 64-bit installation btw.
>>
>> Thanks in advance.
>>
>>
>> 2009/4/13 Stefan de Konink <stefan@xxxxxxxxx>:
>>>
>>> Ravikesh Chandra wrote:
>>>>
>>>> Hi folks,
>>>>
>>>> Firstly I am running CentOS 5.3 with Xen 3.3.1 (gitco) and I've just
>>>> been testing the performance with the Unixbench test. What I found is
>>>> that running the test on the Dom0 (under Xen kernel) resulted in only
>>>> 50% performance of native! I appreciate there is always going to be
>>>> overheads with virtualisation but I just wanted to check with the list
>>>> if these numbers were expected? If that doesn't seem normal any
>>>> suggestions on what I could look at?
>>>
>>> no tls cflag is a start.
>>>
>>>
>>> Stefan
>>>
>>> _______________________________________________
>>> Xen-users mailing list
>>> Xen-users@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-users
>>>
>>
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-users
>

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