Re: [PATCH] speed up SATA

[Pavel Machek]

Hi!

> >What about latency?
...
> merged transfer will top out at 8MB.  You don't see that unless 
> you're on a totally quiet machine with tons of free, contiguous 
> pages.  So in practice it winds up being much smaller, the more 
> loaded the system gets (and pagecache gets fragmented).
> 
> Latency definitely changes for the default case, but remember that a 
> lot of that is writeback, or streaming writes.  Latency-sensitive 
> applications already know how to send small or no-wait I/Os, because 

Well, waiting second for read because 32MB write is being done
will not be fun...
-- 
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms         

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