Re: More Slowdown

[Hans Reiser <reiser@namesys.com>]

6% fragmentation is enormous.  You very much need the repacker we have
not yet written.....

remember that one seek and rotate takes ~12 ms, and during that time you
could transfer 50MB*.012 bytes.....

Hans

John Gilmore wrote:

>On Thursday 17 November 2005 12:40, Vladimir V. Saveliev wrote:
>  
>
>>Please try whether the attached patch improves anything. It simplifies
>>fsync by avoid commiting of transactions which do not modify file being
>>fsync-ed.
>>
>>The patch applied to 2.6.14-mm2 with warnings, but that can be ignored.
>>    
>>
>
>I haven't tried this patch yet, but I did try the earlier 'disable fsync 
>completely' patch. In fact, I'm using it right now.
>
>It doesn't help. Therefore, your patch probably won't help either.
>
>OK, disabling fsync does help a *little* bit. But I think that the issue (for 
>me, anyway) isn't sync per se, it's just flat-out access time. Deleteing lots 
>of small files is EXTREMELY slow, but even reading files is slower than it 
>should be. It took no less that 10 minutes to delete an old kernel source 
>tree, for instance. 
>
>It's related to fragmentation, I think. I didn't really notice any speed 
>problems until my hard drive got to about 95% (or so) full. But they haven't 
>gone away, even though usage is now down around 54%.
>
>Hrm... I should be able to check that...
>
>
>About an hour later...
>
>So maybe I was wrong. 6.5% data fragmentation doesn't seem that high. But 
>19.8% tree fragmentation does seem a bit high. 
>
>How should this data be interpreted?
>
>
>#measurefs.reiser4 -T /dev/mapper/e-h -f
>measurefs.reiser4 1.0.5
>Copyright (C) 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by 
>reiser4progs/COPYING.
>
>Tree fragmentation ... done
>0.197747
>
>#measurefs.reiser4 -S -D /dev/mapper/e-h -f
>measurefs.reiser4 1.0.5
>Copyright (C) 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by 
>reiser4progs/COPYING.
>
>Data fragmentation ... done
>0.065593
>Tree statistics ... done
>Packing statistics:
>  Formatted nodes:    3721.29b (90.85%)
>  Branch nodes:       1734.57b (42.35%)
>  Twig nodes:         2886.97b (70.48%)
>  Leaf nodes:         3814.82b (93.14%)
>
>Node statistics:
>  Total nodes:        8543553
>  Formatted nodes:     146354
>  Unformatted nodes:  8397199
>  Branch nodes:           292
>  Twig nodes:           10542
>  Leaf nodes:         8532719
>
>Item statistics:
>  Total items:         637352
>  Nodeptr items:       146353
>  Statdata items:     191218
>  Direntry items:       17512
>  Tail items:          245018
>  Extent items:         36869
>
>
>#
>
>
>  
>