[U-Boot] ext2 file system performance

[U-Boot] ext2 file system performance

[jonsmirl at gmail.com]

The ext2 file system code is reading the kernel image off from my SD
card one sector at a time. Of course this takes 61 seconds to get the
kernel in to memory. Loading the same kernel off from the same SD on
FAT takes less than a second.

Nice quick FAT reads...

reading uImage
JDS start 7c0 count 1
JDS start 9d0 count 2
JDS start 7d0 count 6
JDS start 1aa0 count 1090
JDS start 2b30 count e
JDS start 2b3e count 1

Ext2 takes about 8,000 single sector reads. File is not fragmented, it
is the only file on a freshly formatted volume.
Is there anyway to convince the ext2 code to use larger reads?

-- 
Jon Smirl
jonsmirl at gmail.com

[U-Boot] ext2 file system performance

[Marek Vasut]

Dear jonsmirl at gmail.com,

> The ext2 file system code is reading the kernel image off from my SD
> card one sector at a time. Of course this takes 61 seconds to get the
> kernel in to memory. Loading the same kernel off from the same SD on
> FAT takes less than a second.
> 
> Nice quick FAT reads...
> 
> reading uImage
> JDS start 7c0 count 1
> JDS start 9d0 count 2
> JDS start 7d0 count 6
> JDS start 1aa0 count 1090
> JDS start 2b30 count e
> JDS start 2b3e count 1
> 
> Ext2 takes about 8,000 single sector reads. File is not fragmented, it
> is the only file on a freshly formatted volume.
> Is there anyway to convince the ext2 code to use larger reads?

It's probably best to dive into the code, I can't answer this out of the top of 
my head, maybe someone else can though.

Best regards,
Marek Vasut

[U-Boot] ext2 file system performance

[Jason]

On Thu, Mar 15, 2012 at 09:20:34PM -0400, jonsmirl at gmail.com wrote:
> The ext2 file system code is reading the kernel image off from my SD
> card one sector at a time. Of course this takes 61 seconds to get the
> kernel in to memory. Loading the same kernel off from the same SD on
> FAT takes less than a second.
> 
> Nice quick FAT reads...
> 
> reading uImage
> JDS start 7c0 count 1
> JDS start 9d0 count 2
> JDS start 7d0 count 6
> JDS start 1aa0 count 1090
> JDS start 2b30 count e
> JDS start 2b3e count 1
> 
> Ext2 takes about 8,000 single sector reads. File is not fragmented, it
> is the only file on a freshly formatted volume.
> Is there anyway to convince the ext2 code to use larger reads?

Take a look at my patch submitted here:

http://www.mail-archive.com/u-boot at lists.denx.de/msg80677.html

Let me know if that works for you.

hth,

Jason.

[U-Boot] ext2 file system performance

[jonsmirl at gmail.com]

Much better 3.5 seconds versus the old 61 seconds.

It is still slower than FAT which can load in less than one second.
Can those 40 sequential reads starting at 1034 be combined?

Read trace from EXT2.....
EA3131-NXP # ext2load mmc 0:3 0x30000000 uImage
Loading file "uImage" from mmc device 0:3 (xxa3)
 <2, 0, 204>
 <4, 0, 32>
 <524, 128, 128>
 <1034, 0, 8>
 <1034, 8, 1>
 <1034, 12, 8>
 <1034, 20, 2>
 <1034, 24, 8>
 <1034, 32, 10>
 <1034, 44, 8>
 <1034, 52, 3>
 <1034, 56, 8>
 <1034, 64, 3>
 <1034, 68, 8>
 <1034, 76, 3>
 <1034, 80, 8>
 <1034, 88, 3>
 <1034, 92, 8>
 <1034, 100, 7>
 <1034, 108, 8>
 <1034, 116, 3>
 <1034, 120, 8>
 <1034, 128, 4>
 <1034, 132, 8>
 <1034, 140, 4>
 <1034, 144, 8>
 <1034, 152, 3>
 <1034, 156, 8>
 <1034, 164, 4>
 <1034, 168, 8>
 <1034, 176, 3>
 <1034, 180, 8>
 <1034, 188, 3>
 <1034, 192, 8>
 <1034, 200, 3>
 <1034, 204, 8>
 <1034, 212, 3>
 <1034, 216, 8>
 <1034, 224, 3>
 <1034, 228, 8>
 <1034, 236, 6>
 <4, 0, 32>
 <527, 0, 128>
 <1062, 0, 1024>
 <1086, 0, 1024>
 <1064, 0, 11264>
 <1600, 0, 1024>
 <1602, 0, 1024>
 <1086, 0, 1024>
 <1088, 0, 262144>
 <1600, 0, 1024>
 <2116, 0, 1024>
 <1602, 0, 1024>
 <1604, 0, 262144>
 <2116, 0, 1024>
 <2630, 0, 1024>
 <2116, 0, 1024>
 <2118, 0, 262144>
 <2630, 0, 1024>
 <3144, 0, 1024>
 <2630, 0, 1024>
 <2632, 0, 262144>
 <3144, 0, 1024>
 <3658, 0, 1024>
 <3144, 0, 1024>
 <3146, 0, 262144>
 <3658, 0, 1024>
 <4172, 0, 1024>
 <3658, 0, 1024>
 <3660, 0, 262144>
 <4172, 0, 1024>
 <4686, 0, 1024>
 <4172, 0, 1024>
 <4174, 0, 262144>
 <4686, 0, 1024>
 <5200, 0, 1024>
 <4686, 0, 1024>
 <4688, 0, 262144>
 <5200, 0, 1024>
 <5202, 0, 66560>
2175848 bytes read
EA3131-NXP #


-- 
Jon Smirl
jonsmirl at gmail.com