[Yaffs] [Yaffs-archive] Re: about YAFFS performance

[Charles Manning]

Hello

I was away for a few days so I did not respond to your earlier email.

The overheads in YAFFS associated with reading are very low and performance 
is mainly tied in with reading NAND and verifying. Thus performance is very 
much dependent on various hardware issues, most important are:
* Transfer speed (dependent on the chip select etc timing).
* What verification and ECC you have enabled (and how fasr the CPU can crank 
the data).

I would suggest you first check the read cycle timing on your NAND device. 
Most NAND can cycle in 50nS.

You might also want to enable  CONFIG_YAFFS_USE_GENERIC_RW. This allows YAFFS 
to use the Linux page cache.

-- CHarles


On Wednesday 17 September 2003 18:37, frankie-yang wrote:
> Hi lists,
>  I am now working MIPS 100MHz CPU on linux 2.4.20 with new mtd and YAFFS
> (latest code from CVS) running on real nand(samsung 64M) . While I mount
> /dev/mtdblock/0 with YAFFS on /mnt/yaffs and write a program to test its
> performance, then the speed rate is not good. The read speed rate just
> 1.1Mbytes per seconds! This is not the same with the documentation
> mentioned on CVS.
>
> Any one can tell me why, or give me any suggestion to improve the
> performance ??? And the speed rate listed on Documentation from CVS is
> tested on what environment ????
>
> Thanks in advance
>
> The config what I set while building YAFFS and MTDs
> #
> # Memory Technology Devices (MTD)
> #
> CONFIG_MTD=y
> # CONFIG_MTD_DEBUG is not set
> CONFIG_MTD_PARTITIONS=y
> # CONFIG_MTD_CONCAT is not set
> # CONFIG_MTD_REDBOOT_PARTS is not set
> # CONFIG_MTD_CMDLINE_PARTS is not set
> CONFIG_MTD_CHAR=y
> CONFIG_MTD_BLOCK=y
> # CONFIG_FTL is not set
> # CONFIG_NFTL is not set
>
> #
> # YAFFS
> #
> CONFIG_YAFFS_FS=y
> CONFIG_YAFFS_USE_OLD_MTD=y
> CONFIG_YAFFS_MTD_ENABLED=y
> # CONFIG_YAFFS_USE_NANDECC is not set
> # CONFIG_YAFFS_USE_GENERIC_RW is not set
> CONFIG_YAFFS_DISABLE_WRITE_VERIFY=y
>
>
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