lkml.org 
[lkml]   [2006]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [ANN] Squashfs 3.0 released
Pavel Machek wrote:
> On Fri 17-03-06 12:25:44, Jeff Garzik wrote:
>>I have two routers, ADM5120-based Edimax and LinkSys
>>WRT54G v5, both of which have a mere 2MB of flash, and
>>both use SquashFS to maximize that space. And both are
>>el cheapo, slow embedded processors that run far slower
>>than 300Mhz. I look askance at anyone who wants to make
>>an arbitrary filesystem design decision imposing tons of
>>bytesex upon these lowly devices.
>
>
> gzip is already pretty expensive, I'd say. Is not byteswap lost in
> noise?
>

Perhaps, but almost all the byteswap is performed on the metadata side,
reading directories and inodes, where nearly every byte will need to be
swapped. As inodes are compacted and compressed in 8 KB blocks, and are
on average 15 bytes in size, for each 8 KB decompress you're potentially
doing 8192/15 inode byteswaps. This is probably sufficent to affect
directory search and lookup on a slow processor.

The data path is all gzip overhead (64K datablocks), there is no
byteswap taking place except for the block size integer. Therefore
byteswap doesn't have any affect on reading data.

Phillip
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-03-21 17:04    [W:0.111 / U:1.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site