All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: "Joerg Roedel" <joerg.roedel@amd.com>
Cc: discuss@x86-64.org, "Andi Kleen" <ak@suse.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] optimize and simplify get_cycles_sync()
Date: Tue, 6 Mar 2007 16:25:41 -0800	[thread overview]
Message-ID: <20070306162541.2b8a148d.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070228142554.GE19452@amd.com>

On Wed, 28 Feb 2007 15:25:54 +0100
"Joerg Roedel" <joerg.roedel@amd.com> wrote:

> From: Joerg Roedel <joerg.roedel@amd.com>
> 
> This patch simplifies the get_cycles_sync() function by removing the
> #ifdefs from it. Further it introduces an optimization for AMD
> processors. There the RDTSCP instruction is used instead of CPUID;RDTSC
> which is helpfull if the kernel runs as a KVM guest. Running as a guest
> makes CPUID very expensive because it causes an intercept of the guest.

Problem:

http://test.kernel.org/functional/index.html

lots of builds fell over because their binutils versions don't understand
rdtscp.

I don't know how recently rdtscp support was added to binutils, but
this is likely to be a problem.  Perhaps we can change this patch to
embed the hex code for that opcode instead?

  reply	other threads:[~2007-03-07  0:25 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-28 14:05 [PATCH 0/4] improve alternative instruction code and optimize get_cycles_sync Joerg Roedel
2007-02-28 14:14 ` [PATCH 1/4] i386: extend alternative instructions framework Joerg Roedel
2007-02-28 14:18 ` [PATCH 2/4] x86_64: changes to x86_64 architecture for alternative instruction improvements Joerg Roedel
2007-02-28 14:21 ` [PATCH 3/4] i386: add the X86_FEATURE_SYNC_RDTSC flag Joerg Roedel
2007-02-28 14:25 ` [PATCH 4/4] optimize and simplify get_cycles_sync() Joerg Roedel
2007-03-07  0:25   ` Andrew Morton [this message]
2007-03-09  9:57     ` Joerg Roedel

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=20070306162541.2b8a148d.akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=ak@suse.de \
    --cc=discuss@x86-64.org \
    --cc=joerg.roedel@amd.com \
    --cc=linux-kernel@vger.kernel.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.