>From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
>To: "Gary Thorpe" <gat7634@hotmail.com>
>CC: tech-kern@netbsd.org
>Subject: Re: I/O priorities
>Date: Fri, 21 Jun 2002 11:13:32 -0700
>
>In message <F118uYDlrjbudzxxfYX000261fe@hotmail.com>"Gary Thorpe" writes
> >>From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
>
> >Here is my oversimplistic analysis:
>
>[1.5.2 has fixed buffer cache, which puts an upper bound on how much
>sustained damage an I/O hungry process can do; 1.6 with UBC allows
>more buffering which lets us get into situations where `hogs' do
>sustained damage to real-time tasks]
>
>It's not so over-simplistic. I think the main thing being overlooked
>is that Manuel's case cares about *latency*, not I/O bandwidth.
>
>Some of the proposed solutions seem to miss that. They'd fix the
>problem for a small burst from a high-priority burst, but not fix the
>latency in serving that first request. It's when the low-priority guy
>is doing a pagein for interactive feedback (X) that Manuel cites, and
>there, it's latency that is the real killer.
>

Then why doesn't 1.5.2 exhibit the same problem???

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