XO-1.5 slow disk writes

John Watlington wad at laptop.org
Tue Nov 17 16:43:25 EST 2009

Good catch, Ben!

In fact, I don't think either the XO-1 or XO-1.5 needs to sync
before suspend.    Maybe before a sleep, but not an aggressive

A more vexing problem is not cutting SD power until it has
finished completing its write.   To address that problem, I
propose trac #9692.


On Nov 17, 2009, at 1:03 PM, Benjamin M. Schwartz wrote:

> Daniel Drake wrote:
>> Today I tried to figure out why running "sync" often takes 5-10  
>> seconds
>> or longer. This slows down suspend, where all data is synced to disk.
> On the XO-1, it was necessary to sync before suspend, because there  
> was no
> guarantee that a suspended laptop would reawaken any time soon.  On  
> 1.5
> (and even on XO-1 with newer software) we should have fully working  
> timed
> wakeups.  That means the kernel could set a policy of a "sync every 5
> minutes", and wake up out of suspend in order to perform the sync.   
> This
> is, IMHO, actually better than a "sync on every suspend" policy,  
> because
> it enables things like write combining that improve performance and  
> reduce
> flash wear.
> Of course, getting sync to be very fast would also be nice.
> --Ben
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