Jffs2 and big file = very slow jffs2_garbage_collect_pass

[Matthieu CASTET]

Josh Boyer wrote:
> On Fri, 18 Jan 2008 10:39:29 +0100
> Matthieu CASTET <matthieu.castet at parrot.com> wrote:
> 
> 
>> In my case the mount is ok : less than 5-10s.
>> The platform used is an arm926 @247 Mhz
> 
> Ok, so running at 247MHz your board has to calculate the CRCs on 41324
> nodes before the file can be opened.  I have no idea how long that
> should really take, but you're doing about 57 nodes per second if it's
> taking 12 minutes.
> 
> As Jörn and David suggested, do some profiling to see where it is
> spending most of it's time.
> 
I sent a mail, but  because of Message has a suspicious header, the 
message wait  moderator approval.


In summary,
the code spend lot's of time in the rbtree code (7 minutes) and 4 
minutes in jffs2_get_inode_nodes.


Matthieu


  54366 rb_prev                                  543,6600
  28345 rb_next                                  283,4500
   8602 default_idle                              71,6833
  10251 __raw_readsl                              40,0430
  49648 jffs2_get_inode_nodes                     11,8097
    251 s3c2412_nand_devready                      7,8438
   1222 crc32_le                                   4,8492