linux-kernel - Re: [PATCH 0/7] overlay filesystem: request for inclusion

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Date:	Fri, 10 Jun 2011 19:39:47 -0700
From:	Greg KH <greg@...ah.com>
To:	Anton Altaparmakov <aia21@....ac.uk>
Cc:	Miklos Szeredi <mszeredi@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Whitcroft <apw@...onical.com>, NeilBrown <neilb@...e.de>,
	Miklos Szeredi <miklos@...redi.hu>, viro@...iv.linux.org.uk,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	nbd@...nwrt.org, hramrach@...trum.cz, jordipujolp@...il.com,
	ezk@....cs.sunysb.edu
Subject: Re: [PATCH 0/7] overlay filesystem: request for inclusion

On Thu, Jun 09, 2011 at 11:58:37PM +0100, Anton Altaparmakov wrote:
> > NTFS has been doing nicely in userspace for almost half a decade.  It's
> > not as fast as a kernel driver _could_ be, but it's faster than _the_
> > kernel driver.
> 
> Er, sorry to disappoint but the Tuxera NTFS kernel driver is faster
> than any user space NTFS driver could ever be.  It is faster than
> ext3/4, too.  (-:  To give you a random example on an embedded system
> (800MHz, 512MB RAM, 64kiB write buffer size) where NTFS in user space
> achieves a maximum cached write throughput of ~15MiB/s, ext3 achieves
> ~75MiB/s, ext4 ~100MiB/s and Tuxera NTFS kernel driver achieves
> ~190MiB/s blowing ext4 out of the water by almost a factor of 2 and
> the user space code by more than a factor of 10.  File systems in user
> space have their applications but high performance is definitely not
> one of them...  You might say that ext3/4 are journalling so not a
> fair comparison so let me add that FAT32 achieves about 100MiB/s in
> the same hardware/test, still about half of NTFS.

Talk to Tuxera, they have a new version of their userspace FUSE version
that is _much_ faster than their public one, and it might be almost as
fast as their in-kernel version for some streaming loads (where caching
isn't necessary or needed.)

So it can be done, and done well, if you know what you are doing :)

thanks,

greg k-h
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