All of lore.kernel.org
 help / color / mirror / Atom feed
From: Zachary Amsden <zach@vmware.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org,
	Virtualization Mailing List <virtualization@lists.osdl.org>
Subject: Re: system call time increase when turning on CONFIG_PARAVIRT
Date: Fri, 02 Mar 2007 23:00:59 -0800	[thread overview]
Message-ID: <45E91D2B.9040004@vmware.com> (raw)
In-Reply-To: <45E8BE79.40200@goop.org>

Jeremy Fitzhardinge wrote:
> Tim Chen wrote:
>   
>> I also hope that the performance can be recovered as this option could
>> enabled in distributions' kernels in future.
>>     
>
> Yes, the intent is that running a CONFIG_PARAVIRT kernel on native
> hardware will have negligible performance hit compared to running a
> non-paravirt kernel.
>   

We can validate that claim entirely.  The way we are proceeding, the 
native code will be inlined or direct called as much as possible.  With 
the VMI-Linux code we had earlier, this mostly created <3% overhead for 
microbenchmarks (and in some cases, we actually won over the unmodified 
native code).  For macro-benchmarks, with real-world workloads, this 
reduced to immeasurable noise, never off by more than +/- 0.5% IIRC.

I believe all of this is totally achievable.  We have the technology.  
We can rebuild it.

Zach

  reply	other threads:[~2007-03-03  7:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-02 20:11 system call time increase when turning on CONFIG_PARAVIRT Tim Chen
2007-03-02 21:54 ` Jeremy Fitzhardinge
2007-03-02 21:54   ` Jeremy Fitzhardinge
2007-03-02 23:11   ` Tim Chen
2007-03-03  0:16     ` Jeremy Fitzhardinge
2007-03-03  0:16       ` Jeremy Fitzhardinge
2007-03-03  7:00       ` Zachary Amsden [this message]
2007-03-08  0:02       ` Tim Chen
2007-03-08  0:02         ` Tim Chen
2007-03-08  0:55         ` Jeremy Fitzhardinge
2007-03-08  0:55           ` Jeremy Fitzhardinge

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=45E91D2B.9040004@vmware.com \
    --to=zach@vmware.com \
    --cc=jeremy@goop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=tim.c.chen@linux.intel.com \
    --cc=virtualization@lists.osdl.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.