kernel defconfig, CONFIG_MTD_NAND_VERIFY_WRITE

Patryk Benderz Patryk.Benderz at esp.pl
Wed Jan 6 16:16:55 CET 2010


Dnia 2010-01-06, śro o godzinie 12:49 +0300, Gennady Kupava pisze:
> hi all,
> 
> I still don't beleive our device should be so slow as it is now. I'll
> try to investigate performance impact of several kernel option. I
> expect, changes will be introduced to defalt config for distributions.
> Here is first one CONFIG_MTD_NAND_VERIFY_WRITE.
> 
> Now it is enabled.
> 
> I build kernel with and without this option, and did read and write
> tests to /dev/mtd6 and /dev/mtdblock6. all tests done with dd
> to/from /dev/zero bs=256k count=200. read is just for check.
> 
> most data in Mb/s.
> 
>               mtd6-rd, mtd6-wt, mtdblock6-rd, mtdblock6-wt
> 
> option on     5.2,     4.8,     2.6,          900kb/s
> 
> option off    5.2,     2.4,     2.6, 	      712kb/s
> 
Well, if this test was repeated several times with similar results, it
might be worth to disable this option IMHO. Only one thing makes me
dither. Will this be safe? I mean, what if there is some software which
takes advantage of this option? Maybe some kind of software which
verifies (using this kernel option) what it writes to device?
Just a thought...

-- 
Patryk "LeadMan" Benderz
Linux Registered User #377521
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