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List:       reiserfs-devel
Subject:    (reiserfs) Some non-serious profiling using gdbstub, slightly interesting
From:       Hans Reiser <reiser () idiom ! com>
Date:       1999-02-17 4:07:53
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"Yury Y.Rupasov" wrote:

> Hello, Hans
>
> I removed Volodya's bugs from reiserfs code and ran gdbstub.
> I tested how reiserfs works with small files.
>
> I did some commands:
>
> mkreiserfs /dev/hdc3
> mount -t reiserfs /dev/hdc3 /mnt
> cd /mnt
> mk dir1
> cd /mnt/dir1
>
> Then :
>
> 1. f1 - file 55 bytes long.
>
>    cp f1 f2
>              search_by_key  11 times stopped
>              fix_nodes      6  times stopped
>              do_balance     3  times stopped
>
> 2. cat f1 f2 > f3
>              search_by_key  15 times stopped
>              fix_nodes      8  times stopped
>              do_balance     4  times stopped
> 3. cp f3 f4
>              search_by_key  11 times stopped
>              fix_nodes      6  times stopped
>              do_balance     3  times stopped
> 4. rm f3
>              search_by_key  7  times stopped
>              fix_nodes      6  times stopped
>              do_balance     3  times stopped
>
> 5. cp 2_byte_file f5
>              search_by_key  11 times stopped
>              fix_nodes      6  times stopped
>              do_balance     3  times stopped

So, my question is, when we cp a small 2k file, on average, how many k of bytes do we memcpy?

If this is a hard question, taking more than an hour or two to measure, don't spend time on it....

Best,

Hans

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