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    SubjectRe: 2.1.114 VFS code 5x slower than 2.0.33?!?
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    Andi Kleen <ak@muc.de> writes:

    [hate to follow myself up, but ...]

    > I repeated your tests with kernel profiling on 2.1.114:
    >
    > Creation:
    > 28.42user 59.63system 2:18.66elapsed 63%CPU (0avgtext+0avgdata 0maxresident)k
    > 0inputs+0outputs (710242major+390114minor)pagefaults 0swaps
    >
    > ...
    > 64 1.05% c011ab7c zap_page_range
    > 68 1.11% c011a9b4 copy_page_range
    > 81 1.33% c01383e0 ext2_get_group_desc
    > 95 1.56% c0126134 get_hash_table
    > 98 1.61% c010ada0 show_registers (this appears often in
    > other kernel profiles too - anyone know the reason?)
    > 111 1.82% c013a994 ext2_new_inode
    > 192 3.16% c011d988 filemap_nopage
    > 382 6.28% c01396c0 ext2_readdir
    > 463 7.62% c011b384 do_wp_page
    > 823 13.54% c013c6e0 ext2_find_entry
    > 953 15.68% c013ca38 ext2_add_entry
    > 1263 20.79% c013960c ext2_check_dir_entry
    ^^^^^^^^^^^^^^^^^^^^^^
    This is bogus. ext2_check_dir_entry is just a small function that does
    some check - it should never take up that much run time. Anyone have any
    theories on this? Or is my profile hosed, can anyone else reproduce it?

    I instrumented my kernel and in about 3h of moderate X11 usage it called
    ext2_check_dir_entry 1520890 times, which seems a bit high.

    -Andi

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