Re: Memory de-duplication (Persistent pages)

["Pasi Kärkkäinen" <pasik@iki.fi>]

On Thu, Sep 16, 2010 at 09:22:29AM -0700, Dan Magenheimer wrote:
>    This is an interesting idea, but  (1) there is no "standard " GPU so I
>    don't think it will be possible to write Xen code generically for this;
>

How about things like OpenCL ? 

-- Pasi

>    (2) most of the overhead for searching will be in moving data from RAM to
>    cache... the CPU overhead is probably a small fraction so a GPU may not
>    help much (unless it has a much wider bus to RAM); (3) in tmem's current
>    deduplication implementation, the search is done synchronously on every
>    put_page... I don't know if this will work well asynchronously due to
>    locking, existing data structures, etc.
> 
>    Dan
> 
> 
> 
>    From: Kaustubh Kabra [mailto:kaustubhwise@gmail.com]
>    Sent: Wednesday, September 15, 2010 1:09 PM
>    To: Xen-devel
>    Cc: Dan Magenheimer
>    Subject: Re: [Xen-devel] Memory de-duplication (Persistent pages)
> 
> 
> 
>    To solve memory deduplication in Xen using Gpu :
> 
>    Current problem :
>    If Memory deduplication is done on Cpu ,a lot of memory is used for data
>    structures and lot of computation time is wasted in finding duplicate page
>    and becomes waste, if duplicate page is not found.
> 
>    Proposed GPU solution: Let Gpu perform seraching for a shared page using
>    multiple threads in parallel,improving searching operation and save data
>    structures on GPU device memory ,which is possible. Communication between
>    Cpu and Gpu can be done using inter processor synchronization which is
>    also possible. Cpu process will run as a daemon that will invoke gpu
>    process when ever deduplication is scheduled / if performance is good
>    enough then for every page written in memory.
> 
>    Correct me , if anything is wrong.
> 
>    On Mon, Sep 6, 2010 at 11:05 PM, Dan Magenheimer
>    <[1]dan.magenheimer@oracle.com> wrote:
> 
>    In my opinion, both could be useful projects.
> 
>    > -----Original Message-----
>    > From: Kaustubh Kabra [mailto:[2]kaustubhwise@gmail.com]
>    > Sent: Saturday, September 04, 2010 1:02 PM
>    > To: Xen-devel
>    > Cc: Dan Magenheimer
>    > Subject: Re: [Xen-devel] Memory de-duplication (Persistent pages)
>    >
> 
>    > Sir,
>    >
>    > We are pretty clear with the internal working of tmem.
>    > Now as "ephemeral" pages are already de-duplicated in current
>    > implementation .
>    >
>    > 1>>So, we propose to do sharing of "persistent" pages also .
>    > 2>>We also propose n/w bipass manager for "tmem" as its not existing
>    > currently.
>    >
>    > Will it be really useful ?
>    > If yes, it will be implemented within stipulated time frame.
>    >
>    > Thank you.
> 
>    --
>    Kaustubh Kabra
>    [3]http://www.kaustubhwise.000a.biz
> 
> References
> 
>    Visible links
>    1. mailto:dan.magenheimer@oracle.com
>    2. mailto:kaustubhwise@gmail.com
>    3. http://www.kaustubhwise.000a.biz/

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