Re: allocating 14KB memory per packet compression/decompression results in vm_fault

From: Giorgos Keramidas (keramida_at_ceid.upatras.gr)
Date: 11/04/05

  • Next message: Ruslan Ermilov: "Re: troubles with ng_fec on -current" 
    Date: Fri, 4 Nov 2005 14:50:16 +0200
To: kamal kc <kamal_ckk@yahoo.com>

    On 2005-11-03 22:56, kamal kc <kamal_ckk@yahoo.com> wrote:
    >>> for my compression/decompression i use string tables and
    >>> temporary buffers which take about 14KB of memory per
    >>> packet.
    >>
    >> If you're allocating 14 KB of data just to send
    >> (approximately) 1.4 KB
    >> and then you throw away the 14 KB immediately, it
    >> sounds terrible.
    >
    > yes that's true.
    >
    > since i am using the adaptive LZW compression scheme it
    > requires construction of string table for
    > compression/decompression. So an ip packet of size 1500 bytes
    > requires a table of size (4KB + 4KB + 2KB = 12KB).

    I may be stating the obvious or something totally wrong, but
    couldn't the string table be constructed once instead of each
    time a packet goes down? It is my intuition that this would
    perform much much better than re-doing the work of the string
    table each time a packet goes out.

    > what would be the best possible way to allocate/deallocate 14KB
    > memory per packet without causing vm_faults ??

    Bearing in mind that packets may be as small as 34 bytes, there's
    no good way, IMHO.

    - Giorgos

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  • Next message: Ruslan Ermilov: "Re: troubles with ng_fec on -current"

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