On 09/05/2013 02:35 AM, Theodore Ts'o wrote:
> How did you gather these results? The mbcache is only used if you are
> using extended attributes, and only if the extended attributes don't
> fit in the inode's extra space.
>
> I checked aim7, and it doesn't do any extended attribute operations.
> So why are you seeing differences? Are you doing something like
> deliberately using 128 byte inodes (which is not the default inode
> size), and then enabling SELinux, or some such?
>
> - Ted
>
No, I did not do anything special, including changing an inode's size. I just used the profile data, which indicated mb_cache module as one of the bottleneck. Please see below for perf data from one of th new_fserver run, which also shows some mb_cache activities.
|--3.51%-- __mb_cache_entry_find
| mb_cache_entry_find_first
| ext4_xattr_cache_find
| ext4_xattr_block_set
| ext4_xattr_set_handle
| ext4_initxattrs
| security_inode_init_security
| ext4_init_security
| __ext4_new_inode
| ext4_create
| vfs_create
| lookup_open
| do_last
| path_openat
| do_filp_open
| do_sys_open
| SyS_open
| sys_creat
| system_call
| __creat_nocancel
| |
| |--16.67%-- 0x11fe2c0
| |
Thanks,
Mak.
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