From: Russell King <rmk@arm.linux.org.uk>
To: Robert Love <rml@tech9.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 2.5: preemptive kernel on UP
Date: Tue, 5 Mar 2002 00:43:25 +0000 [thread overview]
Message-ID: <20020305004325.C32309@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1015287099.865.3.camel@phantasy>
In-Reply-To: <1015287099.865.3.camel@phantasy>; from rml@tech9.net on Mon, Mar 04, 2002 at 07:11:23PM -0500
On Mon, Mar 04, 2002 at 07:11:23PM -0500, Robert Love wrote:
> During 2.5.5-pre, an optimization was made that removed schedule_tail
> from UP kernels. This causes the initial preempt_count of a new task,
> which starts at 1, to never decrement to zero and thus never become
> preemptible.
>
> Thanks to everyone who pointed out the lousy performance - it took
> awhile to find but it should be fixed now. Please comment if not.
>
> Patch is against 2.5.6-pre2 and is critical for all UP+preempt users.
>
> Robert Love
>
> diff -urN linux-2.5.6-pre2/arch/alpha/kernel/entry.S linux/arch/alpha/kernel/entry.S
> --- linux-2.5.6-pre2/arch/alpha/kernel/entry.S Fri Mar 1 17:21:14 2002
> +++ linux/arch/alpha/kernel/entry.S Mon Mar 4 17:49:27 2002
> @@ -495,7 +495,7 @@
> ret $31,($26),1
> .end alpha_switch_to
>
> -#ifdef CONFIG_SMP
> +#ifdef CONFIG_SMP || CONFIG_PREEMPT
Surely you really don't mean this?
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
next prev parent reply other threads:[~2002-03-05 0:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-05 0:11 [PATCH] 2.5: preemptive kernel on UP Robert Love
2002-03-05 0:43 ` Russell King [this message]
2002-03-05 0:51 ` Robert Love
2002-03-05 0:53 ` Russell King
2002-03-05 0:58 ` Robert Love
2002-03-05 1:55 ` Alan Cox
2002-03-05 1:43 ` Robert Love
2002-03-05 4:40 ` Ben Clifford
2002-03-05 1:56 ` yodaiken
2002-03-06 19:17 ` george anzinger
2002-03-06 20:21 ` Robert Love
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=20020305004325.C32309@flint.arm.linux.org.uk \
--to=rmk@arm.linux.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=rml@tech9.net \
/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.