Re: [PATCH 04/16] radix-tree: look-aside cache

[Wu Fengguang <wfg@mail.ustc.edu.cn>]

On Fri, Nov 18, 2005 at 07:25:01PM +0800, Wu Fengguang wrote:
> I run two rounds of oprofile on the context based method, which is the user of
> radix_tree_lookup_{head,tail}, which take advantage of the look-aside cache.
> This is the diffprofile grep output(disable vs. enable cache):
> 
> radixtree-lookaside-cache.diffprofile1:        -8   -53.3% radix_tree_lookup_head
> radixtree-lookaside-cache.diffprofile1:       -30    -7.8% radix_tree_lookup_node
> radixtree-lookaside-cache.diffprofile1:       -34   -18.9% radix_tree_insert
> 
> radixtree-lookaside-cache.diffprofile2:        16    10.9% radix_tree_insert
> radixtree-lookaside-cache.diffprofile2:        12    18.8% radix_tree_preload
> radixtree-lookaside-cache.diffprofile2:         6    42.9% radix_tree_lookup_tail
> radixtree-lookaside-cache.diffprofile2:        -7   -63.6% radix_tree_lookup_head
> radixtree-lookaside-cache.diffprofile2:       -23   -10.5% radix_tree_delete
> radixtree-lookaside-cache.diffprofile2:       -29    -6.9% radix_tree_lookup_node

The above profile data are gathered on comparing two big files:

# du /temp/kernel/bigfile*
626M    /temp/kernel/bigfile
626M    /temp/kernel/bigfile2

I run another real life test:

# grep -r 'asdfghjkl;' /backup/test/linux-2.6.14-rc4-git4-orig/

radixtree-lookaside-cache.diffprofile3:        16    43.2% radix_tree_tag_clear
radixtree-lookaside-cache.diffprofile3:         8    24.2% radix_tree_tag_set
radixtree-lookaside-cache.diffprofile3:        -9    -5.8% radix_tree_lookup_node

radixtree-lookaside-cache.diffprofile4:         7     4.5% radix_tree_lookup_node
radixtree-lookaside-cache.diffprofile4:        -8   -11.8% radix_tree_tag_clear

As expected, there's no noticable difference for small files.

Regards,
Wu