Re: stochastic fair queueing in the elevator [Re: [BENCHMARK] 2.4.20-ck3 / aa / rmap with contest]

[Andrea Arcangeli]

On Mon, Feb 10, 2003 at 11:14:45PM +1100, Nick Piggin wrote:
> Andrea Arcangeli wrote:
> 
> >On Mon, Feb 10, 2003 at 10:53:27PM +1100, Nick Piggin wrote:
> >
> >>Andrew Morton wrote:
> >>
> >>
> >>>Andrea Arcangeli <[e-mail]> wrote:
> >>>
> >>>
> >>>>It's the readahead in my tree that allows the reads to use the max scsi
> >>>>command size. It has nothing to do with the max scsi command size
> >>>>itself.
> >>>>
> >>>>
> >>>Oh bah.
> >>>
> >>>-               *max_ra++ = vm_max_readahead;
> >>>+               *max_ra = ((128*4) >> (PAGE_SHIFT - 10)) - 1;
> >>>
> >>>
> >>>Well of course that will get bigger bonnie numbers, for exactly the 
> >>>reasons
> >>>I've explained.  It will seek between files after every 512k rather than
> >>>after every 128k.
> >>>
> >>>
> >>Though Andrea did say it is a "single threaded" streaming read.
> >>
> >
> >yes, I pointed you to bonnie read sequential in bigbox.html, not
> >tiobench.
> >
> The same pattern is also observed with single threaded tiobench
> anyway.

yes, of course.

Andrea