Re: [Ext2-devel] Re: [RFC][PATCH 0/2]Extend ext3 filesystem limit from 8TB to 16TB

[Laurent Vivier <Laurent.Vivier@bull.net>]

Le jeu 20/04/2006 à 16:39, Laurent Vivier a écrit : 
> The functions added by my patch are following and as they are atomic
> (one machine instruction) they are not measurable and don't appears in
> oprofile.
> 
> atomic_long_add
> atomic_long_read
> atomic_long_set
> atomic_long_inc

I think, as these commands are atomic/inlined we should measure the time
of the functions modified by the patches.

The functions modified by the patch are:

ext3_free_blocks_sb
ext3_has_free_blocks
ext3_new_block
ext3_put_super
ext3_fill_super
ext3_fill_super
ext3_free_inode
find_group_dir
find_group_orlov
ext3_new_inode
ext3_group_add

If we make a "grep" on tiobench oprofile.out, we have:

atomic_t:

26919     0.0119  vmlinux                  vmlinux                  ext3_new_block
2195     9.7e-04  vmlinux                  vmlinux                  ext3_free_blocks_sb
1192     5.2e-04  vmlinux                  vmlinux                  ext3_has_free_blocks
189      8.3e-05  vmlinux                  vmlinux                  ext3_new_inode
40       1.8e-05  vmlinux                  vmlinux                  ext3_free_inode
2        8.8e-07  vmlinux                  vmlinux                  find_group_orlov

percpu_counter:

16290     0.0067  vmlinux                  vmlinux                  ext3_new_block
2075     8.5e-04  vmlinux                  vmlinux                  ext3_free_blocks_sb
428      1.8e-04  vmlinux                  vmlinux                  ext3_has_free_blocks
162      6.7e-05  vmlinux                  vmlinux                  ext3_new_inode
25       1.0e-05  vmlinux                  vmlinux                  ext3_free_inode

As we can using atomic_long_t is slower than percpu_counter so ...
forget my patch.

Regards,
Laurent 

-- 
Laurent Vivier
Bull, Architect of an Open World (TM)
http://www.bullopensource.org/ext4

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