LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Zachary Amsden <zach@vmware.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Alan <alan@lxorguk.ukuu.org.uk>,
	Rusty Russell <rusty@rustcorp.com.au>, Andi Kleen <ak@muc.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Chris Wright <chrisw@sous-sol.org>
Subject: Re: [PATCH 9/11] Panic delay fix
Date: Thu, 15 Feb 2007 15:42:59 -0800	[thread overview]
Message-ID: <45D4F003.4030502@vmware.com> (raw)
In-Reply-To: <20070215101713.GK26240@elf.ucw.cz>

Pavel Machek wrote:
>
> You know it is ugly. Alan demonstrated it even hurts performance, but
> being ugly is the main problem.
>   

No argument with that.  Well, we're ok with dropping it.  Actually, 
reverting the entire set of udelay changes now seems wise.  The same bug 
that happened with i8042 can happen with any hardware device driven by 
the VM in passthrough mode - potentially USB or IDE CDROM or direct SCSI.

Since that is per-device and not global, a global udelay disable really 
is broken in that case, and recompiling individual C files or modules 
for passthrough vs. non-passthrough is not the answer.

So Rusty, Chris, Jeremy, any objections to killing udelay() and friends 
in paravirt-ops?  It would simplify things a bit.  The only thing we 
lose is a slightly faster boot time in the 100% emulated device case.  
I'm ok with losing that.  Even the PIT fast paths don't use udelay, so I 
don't think we care for runtime performance at all.

Zach

  reply	other threads:[~2007-02-15 23:43 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-06  3:53 Zachary Amsden
2007-02-06 12:27 ` Andi Kleen
2007-02-06 21:59   ` Zachary Amsden
2007-02-07 12:35     ` Pavel Machek
2007-02-07 20:36       ` Rusty Russell
2007-02-07 22:23         ` Zachary Amsden
2007-02-08 14:43         ` Dmitry Torokhov
2007-02-08 21:26           ` Zachary Amsden
2007-02-08 21:37             ` Dmitry Torokhov
2007-02-14 12:26         ` Pavel Machek
2007-02-14 19:47           ` Zachary Amsden
2007-02-14 12:52         ` Alan
2007-02-14 20:04           ` Zachary Amsden
2007-02-14 21:34             ` Alan
2007-02-14 21:53               ` Zachary Amsden
2007-02-15  0:33                 ` Alan
2007-02-15 10:17             ` Pavel Machek
2007-02-15 23:42               ` Zachary Amsden [this message]
2007-02-15 23:49                 ` Pavel Machek
2007-02-15 23:50                 ` Jeremy Fitzhardinge
2007-02-16  3:22                 ` Rusty Russell
2007-02-07 14:58     ` Dmitry Torokhov
2007-02-07 22:31       ` Zachary Amsden
2007-02-08  8:24         ` Andi Kleen
2007-02-08  9:08           ` Zachary Amsden
2007-02-08 13:33             ` Andi Kleen
2007-02-08 14:41               ` Dmitry Torokhov
2007-02-14 12:49             ` Alan
2007-02-14 22:51 ` Rusty Russell
2007-02-15  0:28   ` Alan
2007-02-15 13:35   ` Dmitry Torokhov

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=45D4F003.4030502@vmware.com \
    --to=zach@vmware.com \
    --cc=ak@muc.de \
    --cc=akpm@osdl.org \
    --cc=alan@lxorguk.ukuu.org.uk \
    --cc=chrisw@sous-sol.org \
    --cc=jeremy@goop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pavel@ucw.cz \
    --cc=rusty@rustcorp.com.au \
    --subject='Re: [PATCH 9/11] Panic delay fix' \
    /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).