Re: Awful NFS performance with attached test program

[Jan Dittmer <j.dittmer@portrix.net>]

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jlnance@unity.ncsu.edu wrote:
> On Mon, Jan 19, 2004 at 04:53:46PM -0500, Trond Myklebust wrote:
> 
> 
>>So you are surprised that writing the same dataset by putting one
>>integer onto each kernel page takes much more time than placing the
>>entire dataset onto just a few kernel pages? 'cos I'm not...
> 
> 
> I must admit that I am.  I could see that it would take somewhat longer
> because a logicial way for the kernel to implement this would be as a
> read-modify-write operation.  So a 2X slowdown would not supprise me.
> But the slowdown is more than 10X, and that does.
> 
> Also, for what its worth, Solaris performs like this:
> 
>     flame> ./a.out 
>     Creating file: 3.886 seconds
>     Updating file: 1.259 seconds
> 
> While Linux performs like this:
> 
>     jesse> ./a.out
>     Creating file: 43.042 seconds
>     Updating file: 555.796 seconds

My Client (2.6.1-mm2) against my server (2.6.1-bk6) is significantly faster:

./nfstest
Creating file: 11.607 seconds
Updating file: 35.885 seconds

Note the increase of the factor 3 only instead of 10.
nfs mount options: 
rw,hard,intr,rsize=8192,wsize=8192,timeo=30,retrans=10,tcp

Thanks,

Jan

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