Re: [fuse-devel] Patch creation : direct_io option in fuse works in combination with "use sendfile = yes" option in samba

[Samuel G. <sam...@ve...>]

Miklos Szeredi wrote:
> On Tue, 26 May 2009, Samuel Gallard wrote:
>   
>> First of all, I apologise to write to you directly but I am not able to 
>> post any message in the fuse list in Gmane.
>>
>> I hope you will understand.
>>
>> *************************************
>>
>> Hello Miklos,
>>
>> This message follows the conversation "Fuse with direct_io option does 
>> not work via Samba".
>>
>> I have made a lot of tests to see the performance differences between 
>> fuse and a normal mount. it appears the performance decrease 
>> significantly for a normal mount with sendfile =no in samba.
>>
>> I do not know if it also impact the performance for fuse.
>>
>> As I need to have on the same machine some normal mounts and fuse 
>> mounts, is there any way a patch could be created to have this fixed 
>> before kernel 2.6.31 released?
>>     
>
> Sure, the patches are now queued in Jens Axboe's git tree:
>
> http://git.kernel.org/?p=linux/kernel/git/axboe/linux-2.6-block.git;a=shortlog;h=for-2.6.31
>
>   
>> I am sure it can improve performances for fuse in order to have almost 
>> the same than a normal mount over samba.
>>     
>
> Maybe, I wouldn't get my hopes up too high.  Fuse does have some
> performance problems yet.
>
> Please let me know what result you get.
>
> Thanks,
> Miklos
>
>   
The configuration :

- For the test the server is connected to another machine directly in a private network with a gigabyte connection.

-kernel 2.6.28-10 compile with the two options :

 -> VM_MAX_READAHEAD 4096

 -> FUSE_MAX_PAGES_PER_REQ 256

- fuse 2.8.0 pre2

 -> MIN_BUFSIZE 0x401000

I mount the directory with fuse : option big_writes,direct_io 

The Results :

This is the results I got for the moment transferring over Samba:

- one big file copy to the server : 

        70 Mo/s in normal, 55 Mo/s via Fuse

- one big file copy from the server : 

        98 Mo/s in normal, 97  Mo/s via Fuse

- a directory copy (little files) to the server : 

        5 Mo/s in normal, 3 Mo/s via Fuse

- a directory copy (little files) from the server : 

        3.5 Mo/s in normal, 3 Mo/s via Fuse

The normal result are obtained using the option "use sendfile = yes" in samba whereas fuse use the same option as no.

Please let me know know if the lost of performances is normal 

Regards

Samuel