WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Re: lmbench lat_mmap slowdown with CONFIG_PARAVIRT

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: lmbench lat_mmap slowdown with CONFIG_PARAVIRT
From: Ingo Molnar <mingo@xxxxxxx>
Date: Tue, 27 Jan 2009 08:59:12 +0100
Cc: Zachary Amsden <zach@xxxxxxxxxx>, Nick Piggin <npiggin@xxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, "jeremy@xxxxxxxxxxxxx" <jeremy@xxxxxxxxxxxxx>, "rusty@xxxxxxxxxxxxxxx" <rusty@xxxxxxxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, "chrisw@xxxxxxxxxxxx" <chrisw@xxxxxxxxxxxx>, "hpa@xxxxxxxxx" <hpa@xxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 27 Jan 2009 00:05:29 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <49790BCC.1040807@xxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <20090120112634.GA20858@xxxxxxx> <20090120140324.GA26424@xxxxxxx> <49763806.5090009@xxxxxxxx> <20090120205653.GA19710@xxxxxxx> <20090121072718.GN24891@xxxxxxxxxxxxx> <4977A051.8050203@xxxxxxxx> <1232663311.16317.176.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <4978F6C6.3090003@xxxxxxxx> <1232664907.16317.182.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <49790BCC.1040807@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.18 (2008-05-17)
* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

>>> Also, I just posted patches to get rid of all pvops calls when 
>>> fetching or setting flags in a pte, which I hope will help.
>>
>> Sounds like it will help.
>
> ...but apparently not.

ping?

This is a very serious paravirt_ops slowdown affecting the native kernel's 
performance to the tune of 5-10% in certain workloads.

It's been about 2 years ago that paravirt_ops went upstream, when you told 
us that something like this would never happen, that paravirt_ops is 
designed so flexibly that it will never hinder the native kernel - and if 
it does it will be easy to fix it. Now is the time to fulfill that 
promise.

        Ingo

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>