Samba write throughput

[Jacky Lam]

On 1/27/2011 2:33 PM, Volker Lendecke wrote:
> On Thu, Jan 27, 2011 at 09:24:57AM +0800, Jacky Lam wrote:
>> On 1/27/2011 12:38 AM, Jeremy Allison wrote:
>>> On Wed, Jan 26, 2011 at 05:51:13PM +0800, Jacky Lam wrote:
>>>> Dear all,
>>>>
>>>>      I setup my Samba server on my machine and get 300Mbps for
>>>> reading from server, but only 170Mbps for writing. I found that
>>>> reading is use a more efficient way to do with sendfile(). But
>>>> writing just use normal file IO and cause too many memory copy. Is
>>>> there any way to trigger (from client) or force the server to use
>>>> recvfile() instead?
>>> http://wiki.samba.org/index.php/Linux_Performance
>>>
>> Thanks. It is new to me, but it doesn't answer why recvfile/splice
>> implementation has not chance to be used when my XP are writing to
>> it. Any other idea?
> Is your system really so CPU-bound? What kind of CPU do you
> have? Atom? ARM? Small MIPS?
>
> Volker
>
Yes, my system is seriously CPU-bound. When I copy a file from PC to my 
MIPS's Samba server, I found that almost 30% CPU time is spending on 
copy_to_user and copy_from_user. But I googled that although recent 
Linux does have recvfile(), but Samba has used splice() to reduce the 
memory copy. That's why I curious.

Jacky