From: "Kevin D. Kissell" <kevink@mips.com>
To: "Jun Sun" <jsun@mvista.com>
Cc: "MIPS/Linux List \(SGI\)" <linux-mips@oss.sgi.com>,
"Daniel Jacobowitz" <dan@debian.org>
Subject: Re: FP emulator patch
Date: Fri, 17 Aug 2001 01:46:40 +0200 [thread overview]
Message-ID: <020001c126ad$bad05e20$0deca8c0@Ulysses> (raw)
In-Reply-To: 3B7C53BA.24B75620@mvista.com
> > > Strange indeed. And note that if the code were correct, your
> > > surmise about the init_fpu() path being "logically the correct"
> > > one would no longer be true - we'd be saving the FPU state of
> > > the current process for no good reason.
> >
> > And note further that, by forcing current->used_math to
> > zero, the old code was in fact driving the signal handler
> > needlessly into the broken code...
> >
>
> By not clearing current->used_math bit, you are in fact restoring an FPU
> context unnecessarily.
And by clearing it, you are destroying an FPU context unnecessarily.
I'll take the overhead, thanks! ;-) Seriously, if that optimization
is really that important, let's find some other mechanism for communicating
to do_cpu() the fact that we're doing a signal.
Regards,
Kevin K.
WARNING: multiple messages have this Message-ID (diff)
From: "Kevin D. Kissell" <kevink@mips.com>
To: Jun Sun <jsun@mvista.com>
Cc: "MIPS/Linux List (SGI)" <linux-mips@oss.sgi.com>,
Daniel Jacobowitz <dan@debian.org>
Subject: Re: FP emulator patch
Date: Fri, 17 Aug 2001 01:46:40 +0200 [thread overview]
Message-ID: <020001c126ad$bad05e20$0deca8c0@Ulysses> (raw)
Message-ID: <20010816234640.WEzE6oAZ4lYsvoAOISVodMaicTmrcdsCj3ixJZ5E2F0@z> (raw)
In-Reply-To: 3B7C53BA.24B75620@mvista.com
> > > Strange indeed. And note that if the code were correct, your
> > > surmise about the init_fpu() path being "logically the correct"
> > > one would no longer be true - we'd be saving the FPU state of
> > > the current process for no good reason.
> >
> > And note further that, by forcing current->used_math to
> > zero, the old code was in fact driving the signal handler
> > needlessly into the broken code...
> >
>
> By not clearing current->used_math bit, you are in fact restoring an FPU
> context unnecessarily.
And by clearing it, you are destroying an FPU context unnecessarily.
I'll take the overhead, thanks! ;-) Seriously, if that optimization
is really that important, let's find some other mechanism for communicating
to do_cpu() the fact that we're doing a signal.
Regards,
Kevin K.
next prev parent reply other threads:[~2001-08-16 23:43 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-16 22:58 FP emulator patch Kevin D. Kissell
2001-08-16 22:58 ` Kevin D. Kissell
2001-08-16 23:14 ` Jun Sun
2001-08-16 23:46 ` Kevin D. Kissell [this message]
2001-08-16 23:46 ` Kevin D. Kissell
-- strict thread matches above, loose matches on Subject: below --
2002-09-10 11:55 Carsten Langgaard
2001-08-16 18:23 Kevin D. Kissell
2001-08-16 18:23 ` Kevin D. Kissell
2001-08-16 18:49 ` Pete Popov
2001-08-16 18:53 ` Daniel Jacobowitz
2001-08-16 19:15 ` Jun Sun
2001-08-16 20:40 ` Kevin D. Kissell
2001-08-16 20:40 ` Kevin D. Kissell
2001-08-16 21:34 ` Jun Sun
2001-08-16 22:33 ` Kevin D. Kissell
2001-08-16 22:33 ` Kevin D. Kissell
2001-08-16 22:38 ` Pete Popov
2001-08-16 22:37 ` Daniel Jacobowitz
2001-08-16 23:12 ` Jun Sun
2001-08-16 23:38 ` Kevin D. Kissell
2001-08-16 23:38 ` Kevin D. Kissell
2001-08-16 19:20 ` Kevin D. Kissell
2001-08-16 19:20 ` Kevin D. Kissell
2001-08-16 20:20 ` Jun Sun
2001-08-15 12:53 Carsten Langgaard
2001-08-15 18:06 ` Daniel Jacobowitz
2001-08-16 0:05 ` Kevin D. Kissell
2001-08-16 0:05 ` Kevin D. Kissell
2001-08-16 4:20 ` Atsushi Nemoto
2001-08-16 12:35 ` Kevin D. Kissell
2001-08-16 12:35 ` Kevin D. Kissell
2001-08-16 7:07 ` Carsten Langgaard
2001-08-16 4:35 ` Atsushi Nemoto
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