2010-08-17 17:19:44     Low Performance with DDR memory

Document created by Aaronwu Employee on Aug 22, 2013
Version 1Show Document
  • View in full screen mode

2010-08-17 17:19:44     Low Performance with DDR memory

Dusko Cencan (GERMANY)

Message: 92523   

 

Hello,

 

We have designed a custom board with the bf548 and 128MB DDR RAM. Acutally it is 2x64MB. All 128MB are recognized and the board is working just fine. It is clocked 525/131 Mhz. I wonder why our application runs at the same speed as on our previous bf527 board with 32MB and slower SDRAM. The Application is quite memory intensive, so I expected a significant performance boost. Our board ist similar to the EZKIT, except that it has a lot of peripherial interfaces. The DDR is the same, but the one with higher max. clock (200Mhz). The DDR chip is MT46V32M16BN-5B:F TR:

 

  download.micron.com/pdf/datasheets/dram/ddr/512MBDDRx4x8x16.pdf

 

 

 

 

 

Uboot is configured with these settings:

 

CONFIG_CLKIN_HZ         25000000

 

CONFIG CLKIN_HALF      0

 

CONFIG_CLKIN_BYPASS   0

 

CONFIG_VCO_MULT       21

 

CONFIG_CCLK_DIV       1

 

CONFIG_SCLK_DIV        4

 

I wonder, if anyone has suggestions how to improve the DDR performance and what could be configured wrong in the kernel/uboot. Right now, the DDR is not working at its max. speed, but should be faster then SDRAM on bf527.

 

Thanks in advance.

 

 

 

Dusko Cencan

QuoteReplyEditDelete

 

 

2010-08-17 17:30:01     Re: Low Performance with DDR memory

Mike Frysinger (UNITED STATES)

Message: 92524   

 

how did you calculate your ddr timings ?  did you use the spreadsheet referenced in the wiki ?

 

  ez.analog.com/docs/DOC-1441

QuoteReplyEditDelete

 

 

2010-08-18 05:43:56     Re: Low Performance with DDR memory

Dusko Cencan (GERMANY)

Message: 92547   

 

Hi Mike,

 

No, I use the default values. I will check the excel timing table. I noticed that there is no register for the bf54x series in this document.

QuoteReplyEditDelete

 

 

2010-08-18 06:32:33     Re: Low Performance with DDR memory

Dusko Cencan (GERMANY)

Message: 92551   

 

There is definitely no settings for the bf54x series mentioned in this document. I also think, this is for SD RAM only.

 

Do you know where I can find a similar document, targeting the bf54x series with DDR RAM?

QuoteReplyEditDelete

 

 

2010-08-18 06:43:37     Re: Low Performance with DDR memory

Michael Hennerich (GERMANY)

Message: 92552      ez.analog.com/docs/DOC-1441

 

This Excel file includes two worksheets one for SDRAM and one for DDR.

 

-Michael

QuoteReplyEditDelete

 

 

2010-08-18 07:03:34     Re: Low Performance with DDR memory

Dusko Cencan (GERMANY)

Message: 92553   

 

Sorry, I missed the second sheet ;-) Thanks

QuoteReplyEditDelete

 

 

2010-08-18 13:37:30     Re: Low Performance with DDR memory

Dusko Cencan (GERMANY)

Message: 92560   

 

OK, I played a bit with clocks and timings. The CCLK/SCLK of 525/131.25Mhz is replaced by 600/150Mhz.

 

The registers for the timings are:

 

ctl0=0x2E0F060D

ctl1=0x20026323

ctl2=0x00000031

 

dhrystone runs 15 % faster now. This is equivalent to the 15% clock increase of CCLK.

 

Strange thing is that the following settings run about 10% slower, but the timings should be faster.

 

ctl0=0x22ce87d0

ctl1=0x20026323

ctl2=0x00000031

QuoteReplyEditDelete

 

 

2010-08-18 16:08:33     Re: Low Performance with DDR memory

Michael Hennerich (GERMANY)

Message: 92565    In order to do real L3 memory benchmarks - you need to turn caches off!

Attachments

    Outcomes