Embedded SDRAM memory tester

Embedded SDRAM memory tester

[Stephen Williams]

Does anybody out there know of a good quality memory stress tester
for embedded use? I have a PPC based system that seems to work
fine in general (linuxppc-2.4) but I'm seeing soem occasional odd
behavior and I would like to eliminate SDRAM as a potential
problem.

To that end, a memory tester a la memtest86 would be really really
nice. Especially if it is bootable via u-boot:-)
--
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."


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Re: Embedded SDRAM memory tester

[Wolfgang Denk]

In message <41140944.2060704@icarus.com> you wrote:
>
> To that end, a memory tester a la memtest86 would be really really
> nice. Especially if it is bootable via u-boot:-)

All of the memtest86 code (and  a  little  more)  _is_  available  in
U-Boot. Just enable it in the configuration.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"Once they go up, who cares where  they  come  down?  That's  not  my
department."                                       - Werner von Braun

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Boot time with several filesystems on RPXlite DW

[Song Sam]

Hi,

I used several filesystems based on MTD vs ramdisk to
test boot time on RPXlite DW and got the following
result:

Common condition:
1) 2.4.18[uncompressed] + 48MHZ[CORE] + 48MHZ[BUS] +
converted SELF
2) console=ttyS0,9600

Filesytem     I       II       III[Total]
ramdisk     01"14    11"97     16"79

JFFS2       01"14    10"07     15"39
Cramfs      01"14    07"60     12"54
Ext2        01"14              13"68

u-boot>run flash_self
            <----------------  START TIME : 00"00
## Booting image at ff080000 ...
   Image Name:   RPXlite DW uncompressed kernel
   Image Type:   PowerPC Linux Kernel Image
(uncompressed)
   Data Size:    1256048 Bytes =  1.2 MB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
OK
             <--------------------- Pharse I
Linux version 2.4.18_ ...
......
Kernel command line: console=ttyS0,9600
root=/dev/mtdblock3 rw
ip=172.16.115.7:172.16.115.6:172.16.115.254:255.255.255.0::eth0:off
panic=1
......
Memory: 62780k available (1008k kernel code, 332k
data, 64k init, 0k highmem)
Dentry-cache hash table entries: 8192 (order: 4, 65536
bytes)
Inode-cache hash table entries: 4096 (order: 3, 32768
bytes)
Mount-cache hash table entries: 1024 (order: 1, 8192
bytes)
Buffer-cache hash table entries: 4096 (order: 2, 16384
bytes)
Page-cache hash table entries: 16384 (order: 4, 65536
bytes)
.....
Creating 3 MTD partitions on "RPX":
0x00000000-0x00080000 : "RPXLITE flash U-BOOT
partition"
0x00080000-0x00200000 : "RPXLITE flash KERNEL
partition"
0x00200000-0x01000000 : "RPXLITE flash APPLICATION
partition"..
......
IP-Config: Complete:
      device=eth0, addr=172.16.115.7,
mask=255.255.255.0, gw=172.16.115.254,
     host=172.16.115.7, domain=, nis-domain=(none),
     bootserver=172.16.115.6, rootserver=172.16.115.6,
rootpath=
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
VFS: Mounted root (jffs2 filesystem).
Freeing unused kernel memory: 64k init
             < ----------------------- Phrase II
My application is running ... Sam Song
         Feb.7,2004

BusyBox v0.60.1 (2002.10.24-04:52+0000) Built-in shell
(msh)
Enter 'help' for a list of built-in commands.

# Hello Shanghai Univ.
Hi Everybody!
             < ----------------------- Phrase III

------------------------------------------------

It seemed that Cramfs filesystem could get the most
fast boot time.Also No matter how I tried,the boot
time still exceeded 12 seconds at least.But this
result is not the same as Wolfgang said,5~6 seconds
boot time on 8xx board with 50MHZ core and bus
frequency.Where did I go wrong?

I would be satisfied with less than 8 seconds in my
case.Any ideas?

Thanks in advance!

Best regards,

Sam

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Re: Boot time with several filesystems on RPXlite DW

[Wolfgang Denk]

In message <20040809145454.46774.qmail@web15609.mail.cnb.yahoo.com> you wrote:
>
> I used several filesystems based on MTD vs ramdisk to test boot time
> on RPXlite DW and got the following result:
...
> It seemed that Cramfs filesystem could get the most fast boot
> time.Also No matter how I tried,the boot time still exceeded 12
> seconds at least.But this result is not the same as Wolfgang said,5~6
> seconds boot time on 8xx board with 50MHZ core and bus frequency.Where
> did I go wrong?

There are many potential problems.

One thing that is obvious is:

You use an uncompressed kernel image, but have the CRC32 checksumming
enabled. This is counterproductive - the uncompressed image is nearly
3 times as big as a compressed one,  so  checksumming  it  will  take
about 3 times as long.

If you want to go for speed and use an uncompressed image, you should
also  turn  off  the  CRC  checksum  test  (by  setting  the   U-Boot
environment variable "verify" to "no").

Then you may try increasing  the  console  baudrate,  or  suppressing
console  output  completely  (pass console=null to the Linux kernel).
Other issues are system dependent. Your system may not  be  optimized
for  minimum  access times for SDRAM and/or flash memory. Your system
might not be using 32 bit buswidth on SDRAM and/or flash. You may  be
running  on a processor which is slower because of small caches (like
a MPC850), etc. etc.

> I would be satisfied with less than 8 seconds in my case.Any ideas?

This is what I get using:

* A MPC860-T at 50 MHz CPU/50 MHz bus, 16 MB RAM.
* Our standard Linux kernel (uncompressed)
* Our standard (uncompressed) SELF image as included with the ELDK
* CRC32 verification turned off

   0.000 START_TEST
   0.090 ## Booting image at 40040000 ...
   0.090    Image Name:   Linux-2.4.4 uncompressed
   0.091    Created:      2004-08-10   7:21:20 UTC
   0.091    Image Type:   PowerPC Linux Kernel Image (uncompressed)
   0.091    Data Size:    1438656 Bytes =  1.4 MB
   0.091    Load Address: 00000000
   0.120    Entry Point:  00000000
   0.200 OK
   0.201 ## Loading RAMDisk Image at 40200000 ...
   0.201    Image Name:   Simple Embedded Linux Framework
   0.201    Created:      2004-08-10   7:23:35 UTC
   0.201    Image Type:   PowerPC Linux RAMDisk Image (uncompressed)
   0.201    Data Size:    4194304 Bytes =  4 MB
   0.270    Load Address: 00000000
   0.270    Entry Point:  00000000
   0.590    Loading Ramdisk to 00bad000, end 00fad000 ... OK
   0.981 Linux version 2.4.4 (wd@atlas.denx.de) (gcc version 3.2.2 20030217 (Yellow Dog Linux 3.0 3.2.2-2a_1)) #2 Thu Jul 22 19:12:37 MEST 2004
   0.981 On node 0 totalpages: 4096
   0.981 zone(0): 4096 pages.
   0.981 zone(1): 0 pages.
   0.981 zone(2): 0 pages.
   1.010 Kernel command line: root=/dev/ram rw ip=192.168.3.71:192.168.3.1::255.255.0.0:tqm8xx:eth0:off panic=1
   1.010 Decrementer Frequency: 3125000
   1.140 Calibrating delay loop... 49.86 BogoMIPS
   1.140 Memory: 10356k available (1144k kernel code, 440k data, 52k init, 0k highmem)
   1.201 Dentry-cache hash table entries: 2048 (order: 2, 16384 bytes)
   1.201 Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
   1.201 Page-cache hash table entries: 4096 (order: 2, 16384 bytes)
   1.201 Inode-cache hash table entries: 1024 (order: 1, 8192 bytes)
   ...
   2.515 TQM flash bank 0: Using static image partition definition
   2.515 Creating 4 MTD partitions on "TQM8xxL Bank 0":
   2.516 0x00000000-0x00040000 : "u-boot"
   2.516 0x00040000-0x00100000 : "kernel"
   2.516 0x00100000-0x00200000 : "user"
   2.516 0x00200000-0x00400000 : "initrd"
   2.516 TQM flash bank 1: Using static file system partition definition
   2.516 Creating 2 MTD partitions on "TQM8xxL Bank 1":
   2.516 0x00000000-0x00200000 : "cramfs"
   2.516 0x00200000-0x00400000 : "jffs"
   2.516 NET4: Linux TCP/IP 1.0 for NET4.0
   2.516 IP Protocols: ICMP, UDP, TCP
   2.517 IP: routing cache hash table of 512 buckets, 4Kbytes
   2.517 TCP: Hash tables configured (established 1024 bind 2048)
   2.517 NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
   2.517 VFS: Mounted root (ext2 filesystem).
   2.517 Freeing unused kernel memory: 52k init
   6.533 ### Application running ...

Without any further optimization (like throwing out  unused  drivers,
disabling  slow  console  output,  using  pre-calculated jiffies-per-
second etc.) your "phase I" is less than 1 second,  your  phase  "II"
takes about 2.5 seconds, and your "phase III" takes 6.5 seconds - but
this is our standard image, which includes some slow operations (like
starting  xinetd)  which  I  normally woould try to avoid or at least
pospone until the  critical  parts  of  the  applications  have  been
started.  By  just  disabling xinetd you will see a boot time of 4..5
seconds on this system.

And as mentioned there is a long list of options to optimize the boot
time.

As you can see there is no magic involved.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
panic: can't find /

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Re: Boot time with several filesystems on RPXlite DW

[Song Sam]

Wolfgang Denk <wd@denx.de> wrote:
> > It seemed that Cramfs filesystem could get the most fast boot
> > time.Also No matter how I tried,the boot time still exceeded 12
> > seconds at least.But this result is not the same as Wolfgang
> > said,5~6 seconds boot time on 8xx board with 50MHZ core and bus
> > frequency.Where did I go wrong?
>
> There are many potential problems.

Thanks for your so detailed reply.I see what I should
improve in the next.

I got a nice instruction from you again.

Thank you so much:-)

Sam

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Re: Boot time with several filesystems on RPXlite DW

[Tom Rini]

On Mon, Aug 09, 2004 at 10:54:54PM +0800, Song Sam wrote:

> I used several filesystems based on MTD vs ramdisk to
> test boot time on RPXlite DW and got the following
> result:
[snip]
> IP-Config: Complete:
>       device=eth0, addr=172.16.115.7,
> mask=255.255.255.0, gw=172.16.115.254,
>      host=172.16.115.7, domain=, nis-domain=(none),
>      bootserver=172.16.115.6, rootserver=172.16.115.6,
> rootpath=
> NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
> VFS: Mounted root (jffs2 filesystem).
[snip]
> I would be satisfied with less than 8 seconds in my
> case.Any ideas?

Try trimming down the .config.  For example, it doesn't look like you
need IP_PNP enabled as you aren't NFSrooting and can just bring the
interface up later.

--
Tom Rini
http://gate.crashing.org/~trini/

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Re: Boot time with several filesystems on RPXlite DW

[Wolfgang Denk]

In message <20040810214757.GL22109@smtp.west.cox.net> you wrote:
>
> Try trimming down the .config.  For example, it doesn't look like you
> need IP_PNP enabled as you aren't NFSrooting and can just bring the
> interface up later.

This depends. If the application needs network access, it is  usually
faster  to  use  IP_PNP  instead  of loading and running ifconfig and
route. [At least under 2.4; don't know timings for 2.6.]

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
I am a computer. I am dumber than any human and smarter than any  ad-
ministrator.

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Re: Boot time with several filesystems on RPXlite DW

[Song Sam]

Wolfgang Denk <wd@denx.de> wrote£º

> > Try trimming down the .config. For example, it doesn't look like you
> > need IP_PNP enabled as you aren't NFSrooting and can just bring the
> > interface up later.
>
> This depends. If the application needs network access, it is usually
> faster to use IP_PNP instead of loading and running ifconfig and
> route. [At least under 2.4; don't know timings for 2.6.]

OK.I tested with no IP_PNP,there was a 2 seconds
decrease on boot time.After setting "verify=no" to
mask CRC32 checksum,the boot time came to 11"78.Then
without IP_PNP,the boot time was 9"69.Close to my
expected 8 seconds.Yeah,there are some special option
in my .config,like framebuffer and USB HOST mode
configuration.

I tried to optimize minimum access times for SDRAM in
U-Boot,almost no obvious improvement.I need time to
optimize SDRAM and FLASH access times.I took
Wolfgang's example to use uncompressed kernel and
ramdisk.

Thanks a lot for your help.

Sam

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Re: Embedded SDRAM memory tester

[Stefan Nickl]

On Sat, 2004-08-07 at 00:42, Stephen Williams wrote:
> Does anybody out there know of a good quality memory stress tester
> for embedded use? I have a PPC based system that seems to work
> fine in general (linuxppc-2.4) but I'm seeing soem occasional odd
> behavior and I would like to eliminate SDRAM as a potential
> problem.

http://www.qcc.ca/~charlesc/software/memtester/

--
Stefan Nickl
Kontron Modular Computers


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