OneNAND: read-while-load

[Adrian Hunter]

On 1/5/07, Kyungmin Park <kyungmin.park at samsung.com> wrote:
> Hi,
>
> it looks good to me. except one
>
> > +     /* Read-while-load method */
> >
> > +     /* Do first load to bufferRAM */
> > +     if (read < len) {
>
> I think it is alway true. Is there any case that sends zero 'len' from upper layer?
>
> I will run regression test with this one during this weekend.
>
> And which program (JFFS2 or UBI) do you use.
>
> I can't find any performance increase in JFFS2
>
> Here's my test results
>
> Target: Apollon (OMAP2) 330MHz, OneNAND 83MHz with Sync. Burst Read support mode
>
> # iozone -U /jffs2 -f /jffs2/test -e -A -s 10m -q 256k
>
> Before patch
>
>               KB  reclen   write rewrite    read    reread
>            10240       4    5961    5942    15667    15677
>            10240       8    6053    6033    15849    15830
>            10240      16    6068    6068    15983    15974
>            10240      32    6091    6088    16098    16083
>            10240      64    6115    6077    16128    16111
>            10240     128    6142    6134    16249    16226
>            10240     256    6138    6147    16184    16212
>
> After patch
>
>               KB  reclen   write rewrite    read    reread
>            10240       4    5931    5914    15598    15577
>            10240       8    6035    5941    15775    15743
>            10240      16    6070    6037    16020    15986
>            10240      32    6098    6081    16140    16115
>            10240      64    6123    6100    16123    16108
>            10240     128    6147    6102    16186    16188
>            10240     256    6134    6114    16142    16152
>
>
> Thank you,
> Kyungmin Park

I will need to study your results more closely, however you won't see
results unless you can exclude the effects of buffering.  I tested
used jffs2 but I used a very simple program that un-mounted and
re-mounted before reading.