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Date: Fri, 28 May 2010 21:38:53 +0530
From: Nitin Gupta <ngupta@vflare.org>
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To: Greg KH <greg@kroah.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>,
       Andrew Morton <akpm@linux-foundation.org>,
       Minchan Kim <minchan.kim@gmail.com>,
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       driverdev <devel@driverdev.osuosl.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] zram: generic RAM based compressed R/W block devices
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Hi All,

On 05/24/2010 07:48 PM, Nitin Gupta wrote:
> Creates RAM based block devices: /dev/zramX (X = 0, 1, ...).
> Pages written to these disks are compressed and stored in memory
> itself. These disks allow very fast I/O and compression provides
> good amounts of memory savings.
> 
> This is enhancement over existing ramzswap driver which creates
> virtual block devices (/dev/ramzswapX) which could be used only
> as swap disks.
> 
> Now, with the ability to handle any kind of I/O request, zram
> devices have lot more use cases:
>  - /tmp storage
>  - various caches under /var
>  - swap disks
>  - maybe even more! :)
> 
> Performance numbers can be found at:
> http://code.google.com/p/compcache/wiki/zramperf
> 

Any reviews/comments, please?

I also performed iozone tests to stress zram:
http://code.google.com/p/compcache/wiki/zramIOzone

Note that the effect of pagecache could not be completely
avoided, even when pagecache was dropped every 1 second.
So, this iozone test should not be considered for speed
measurements but as a stress test only. For speed tests,
you can refer 'dd' test results included in changelog (patch 1).

No errors were observed during either iozone or dd tests.

Thanks,
Nitin