disk devices speed is ugly

Alex Samorukov ml at os2.kiev.ua
Mon Feb 13 06:36:34 UTC 2012

On 02/13/2012 06:27 AM, Adrian Chadd wrote:
> On 12 February 2012 09:34, Alex Samorukov<ml at os2.kiev.ua>  wrote:
>> Yes. But it will nit fix non-cached access to the disk (raw) devices. And
>> this is the main reason why ntfs-3g and exfat are much slower then working
>> on Linux.
> But _that_ can be fixed with the appropriate application of a sensible
> caching layer.
With every application?  :) Are you know anyone who wants to do this? At 
least for 3 fuse filesystems.

Also, caching in user-land is much slower and more dangerous.

There is a libublio utility which is done to provide userland caching 
(it implements pwrite/pread replacement) and it is in use by this 2 ports.

> So if there are alignment issues, let's fix those up first so
> filesystems act sensibly with the block device layer. Then yes, adding
> a caching layer that works. I didn't get very good performance with
> g_cache when i last tried it.
Because its very primitive. Once again - try to compare performance of 
the exfat or ntfs-3g on Linux and FreeBSD. Raw device speed (i used USB) 
is pretty the same, but resulting speed is very different, as well as 
I/O characteristic.

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