[fuse-devel] Fuse performance over ext4 performance

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

Hello,

I am trying to benchmark fuse over the default filesystem. 

For the test, I am using an Ubuntu server 10.04 LTS with a Raid 1 
system in ext4 and the kernel 2.6-38-11-server.

I used fusexmp.c (web.mit.edu/~ecprice/fuse-2.7.0/example/fusexmp.c) with 
the fuse version 2.8.6 which just permits to replace a normal file system.

Did anyone ever succeed to obtain almost the same performance in reading and
writing with Fuse ?

For the moment, I used the following option to tweak Fuse and the kernel :
- VM_MAX_READAHEAD located in /usr/src/linux-headers-2.6.*/include/linux/mm.h
 : 4096
- MIN_BUFSIZE located in */fuse-2.*/lib/fuse_kern_chan.c : 0x401000
- FUSE_MAX_PAGES_PER_REQ located in fs/fuse/fuse_i.h : 256

For the mount point, I have the following options : big_writes, large_read and
direct_io.

To check the performance, I use it over samba (with the option sendfile=yes) 
to write and read files.

I obtain a loss of 10% when writing within the fuse mount point and around a
loss of 50% when reading from it.

Did I miss an option or something ? Or is it a normal behavior ?

Regards

Samuel