LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nick Piggin <npiggin@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arch@vger.kernel.org
Subject: Re: [rfc][patch] x86-64 new smp_call_function design
Date: Wed, 27 Feb 2008 23:14:07 +0100	[thread overview]
Message-ID: <20080227221407.GA26067@wotan.suse.de> (raw)
In-Reply-To: <20080227150210.GA21610@elte.hu>

On Wed, Feb 27, 2008 at 04:02:10PM +0100, Ingo Molnar wrote:
> 
> * Nick Piggin <npiggin@suse.de> wrote:
> 
> > > the two structures are quite similar in size and role - why not have 
> > > a type field and handle them largely together? I think we should try 
> > > to preserve a single queue and a single vector - that would remove a 
> > > number of ugly special-cases from the patch.
> > 
> > A single queue will kill one of the big fundamental scalability 
> > improvements of the call_single. That's the problem.
> 
> hm, indeed. Then how about the other way around: couldnt the normal 
> all-cpus SMP function call be implemented transparently via using 
> smp_call_single() calls?

That's possible, but it is slower and less scalable on my 8-way, and
I suspect it might become even slower than the generic code on larger
systems.

> The vector duplication is really ugly and feels 
> wrong.

Why?

  reply	other threads:[~2008-02-27 22:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-27 12:42 Nick Piggin
2008-02-27 13:04 ` Andi Kleen
2008-02-27 13:07   ` Nick Piggin
2008-02-27 13:33     ` Andi Kleen
2008-03-16 14:33       ` Avi Kivity
2008-02-27 13:27 ` Ingo Molnar
2008-02-27 13:50   ` Nick Piggin
2008-02-27 15:02     ` Ingo Molnar
2008-02-27 22:14       ` Nick Piggin [this message]
2008-02-28  8:45         ` Ingo Molnar
2008-02-28 12:55           ` Andi Kleen

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=20080227221407.GA26067@wotan.suse.de \
    --to=npiggin@suse.de \
    --cc=ak@suse.de \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --subject='Re: [rfc][patch] x86-64 new smp_call_function design' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).