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 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.

Andrea