Huge ubi or ubifs sync slowdown since 2.6.32
manningc2 at actrix.gen.nz
Mon Dec 20 17:36:22 EST 2010
I've been looking into a ubifs performance regression on linux-omap 2.6.37.
My test is pretty simple, copy a 2Mbyte file and sync.
# sync; date; cp 2Mbyte-file foo; sync; date
On 2.6.32 and earler, the time between the two dates was around 3 seconds.
On linux-omap master it is around 14 seconds. Ouch!
At first I thought the problem was due to changes in the OMAP nand drivers,
but raw randwrite speed is actually a bit faster. This suggest the finger
should be pointed at ubi or ubifs.
I then thought that perhaps the layout of my ubinized image might be a
contributing factor so I erased the partition, ubiformatted and ubimkvoled.
The problem persisted,
Any suggestions as to what might be broken or how to debug this deeper?
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