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Re: DFA scheduler patch for review
- From: law at redhat dot com
- To: Mark Mitchell <mark at codesourcery dot com>
- Cc: Gerald Pfeifer <pfeifer at dbai dot tuwien dot ac dot at>, Geoff Keating <geoffk at redhat dot com>, Dave Miller <davem at redhat dot com>, "vmakarov at cygnus dot com" <vmakarov at cygnus dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 30 Apr 2002 10:59:41 -0600
- Subject: Re: DFA scheduler patch for review
- Reply-to: law at redhat dot com
In message <322710000.1020184857@gandalf.codesourcery.com>, Mark Mitchell write
s:
> > Anyway, I really don't expect the DFA scheduler to have the kind of
> > negative impact that the inliner had.
>
> I agree.
>
> The flip side of Jeff's point (that you only get the DFA scheduler where
> it's turned on) is that we now again have two schedulers. It would be
> good if people would collaborate to do DFA schedulers for all the ports
> so that we can lose the old new scheduler.
More correctly, we have two methods for describing a processor pipeline and
two methods for the scheduler to query that information from the backend.
For folks who are considering updating their ports; I would strongly recommend
first converting to a DFA description which produces the same code as the old
description. That will give you familiarity with how to describe pipelines
using the new scheme and you can verify that the description does what you
expect by comparing the old and new schedules. I've found this invaluable
for the PA port.
Once you've got a solid DFA description, then move to trying to improve it
by more accurately describing the various cpu units and reservations.
jeff