From: Daniel Jacobowitz <dan@debian.org>
To: Greg Lindahl <lindahl@keyresearch.com>
Cc: Jun Sun <jsun@mvista.com>, linux-mips@linux-mips.org
Subject: Re: [RFC] FPU context switch
Date: Tue, 17 Sep 2002 15:38:20 -0400 [thread overview]
Message-ID: <20020917193820.GA28255@nevyn.them.org> (raw)
In-Reply-To: <20020917120310.A2043@wumpus.internal.keyresearch.com>
On Tue, Sep 17, 2002 at 12:03:10PM -0700, Greg Lindahl wrote:
> On Tue, Sep 17, 2002 at 11:48:31AM -0700, Jun Sun wrote:
>
> > I think this gives a big performance improvement because most processes
> > don't use FPU during their runs but they all have used_math flag set!
>
> Jun,
>
> You really ought to prove that first. Many people spend a lot of time
> optimizing things that aren't important. If it isn't important, than
> the simplest scheme is the best choice.
Oh, he's quite correct. There's a setjmp() early in the execution
path, and it saves FP registers on machines with FP support configured
on. So tasks are marked as FPU users.
I've never thought of a terribly good way around this.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
next prev parent reply other threads:[~2002-09-17 19:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-17 18:04 [RFC] FPU context switch Jun Sun
2002-09-17 18:31 ` Greg Lindahl
2002-09-17 18:35 ` Jun Sun
2002-09-17 18:42 ` justinca
2002-09-17 18:48 ` Jun Sun
2002-09-17 19:03 ` Greg Lindahl
2002-09-17 19:38 ` Daniel Jacobowitz [this message]
2002-09-17 21:44 ` Dominic Sweetman
2002-09-17 21:58 ` Matthew Dharm
2002-09-17 21:58 ` Matthew Dharm
2002-09-17 22:30 ` Kevin D. Kissell
2002-09-17 22:30 ` Kevin D. Kissell
2002-09-17 22:58 ` Greg Lindahl
2002-09-17 23:03 ` Jun Sun
2002-09-17 23:44 ` Kevin D. Kissell
2002-09-17 23:44 ` Kevin D. Kissell
2002-09-17 23:45 ` Jun Sun
2002-09-18 8:38 ` Kevin D. Kissell
2002-09-18 8:38 ` Kevin D. Kissell
2002-09-18 16:53 ` Jun Sun
2002-09-18 8:29 ` Carsten Langgaard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20020917193820.GA28255@nevyn.them.org \
--to=dan@debian.org \
--cc=jsun@mvista.com \
--cc=lindahl@keyresearch.com \
--cc=linux-mips@linux-mips.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.