Re: RFC on io-stalls patch

[Jeff Garzik]

Chris Mason wrote:
> Well, I'd say it's a more common problem to have lots of writes, but it
> is pretty easy to fill the queue with reads.

Well....

* you will usually have more reads than writes
* reads are more dependent than writes, on the whole
* writes are larger due to delays and merging

All this is obviously workload dependent, but it seems like the 60% 
common case, at least...

Basically when I hear people talking about lots of writes, that seems to 
be downplaying the fact that seeing 20 writes and 2 reads on a queue 
does not take into account the userspace applications currently 
blocking, waiting to do another read.

	Jeff