On Saturday 25 August 2007 11:53:42 Siddharth Choudhuri wrote:
> Hi,
>
> I was looking at the nPageReads counter. It gets incremented inside of
> yaffs_ReadChunkFromNAND() function. Following the function call chain this
> could be in the following case (assuming page not in cache).
> yaffs_readpage() -> ... -> yaffs_ReadChunksWithTagsFromNAND(). Inside
> yaffs_ReadChunkFromNAND function there is the following if statement:
>
> if (dev->readChunkWithTagsFromNAND)
>     result = dev->readChunkWithTagsFromNAND();
> else
>     result = yaffs_TagsCompatabilityReadChunkWithTagsFromNAND();
>
> Now my question is why is nPageRead incremented in the else case [i.e.,
> else condition eventually calls yaffs_ReadChunkFromNAND() which increments
> nPageReads] and not in the if case. Looking at the source code, the if
> condition also leads to a function - nandmtd2_ReadChunkWithTagsFromNAND()
> which does a low level mtd->read().
>
> Am I missing something here ? Basically, I wanted a count of how many NAND
> read pages come from the file system and how many are due to flash
> management.

No I don't think you are missing something. This is a low-flying bug.

The history is that the read/write/erase counting were added a long while ago 
for a once-off profiling exercise and was not kept current. Probably should 
be fixed :-).

-- CHarles

>
> thanks in advance,
> -siddharth
>
>
>
> ___________________________________________________________________________
>_________ Need a vacation? Get great deals
> to amazing places on Yahoo! Travel.
> http://travel.yahoo.com/
>
> _______________________________________________
> yaffs mailing list
> yaffs@lists.aleph1.co.uk
> http://lists.aleph1.co.uk/cgi-bin/mailman/listinfo/yaffs