Re: [Firebird-devel] AutoOptimize

[Alex P. <pe...@in...>]

Vlad Horsun:
>     So the question i want to ask - is anybody have good idea of how to rule
> thread IO priority ? What i want to know is how to rule amount of thread IO 
> requests so that particular thread don't eat many resources when other threads
> have what to do

As far as I know, linux not long ago started experiments with 
process-level IO priority:

http://www.die.net/doc/linux/man/man1/ionice.1.html

And it seems to be not production ready yet :-(. At least CFQ IO 
scheduler, required to set process IO priority, in my experiments gave 
much worse results working with SATA disks compared with traditional 
linux IO scheduler.
Formally it may be useful for CS, but in practice - I don't think so.


We may think about scheduling IO requests in out own code. I.e., if we 
mark some thread as low IO priority, we may delay IO requests from it 
somewhere at CCH/PIO levels. But here it's time to think once again 
about other priorities - priorities of our roadmap...