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/
Home Products Support Community News


Re: [Xen-devel] Possible bugs and doubts about readjusting weights/slice

To: Amitayu Das <amitayudas@xxxxxxxxx>
Subject: Re: [Xen-devel] Possible bugs and doubts about readjusting weights/slice-lengths from command prompt
From: Ryan Harper <ryanh@xxxxxxxxxx>
Date: Wed, 3 May 2006 10:26:49 -0500
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, rhim@xxxxxxxxxxxxx
Delivery-date: Wed, 03 May 2006 08:27:14 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <5f74ce410605022248m31c5de98j95c2dbffd6b5878a@xxxxxxxxxxxxxx>
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <5f74ce410605022248m31c5de98j95c2dbffd6b5878a@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.6+20040907i
* Amitayu Das <amitayudas@xxxxxxxxx> [2006-05-03 00:49]:

> 2. Say, I'm readjusting the slice lengths of running domains. While doing
> that, I make a mistake by having sum of the slice-lengths higher than
> period-length. In such cases, what does Xen actually do? I did not find
> sanity-checking code for such cases in xen/common/sched_sedf.c. Please let
> me know in case it's not there, why so or it's there, only I did not find
> it.

For time-driven domains, versus weighted domains in sched_sedf.c:1407

     * Sanity checking: note that disabling extra weight requires
     * that we set a non-zero slice.
    if ( (cmd->u.sedf.period > PERIOD_MAX) ||
         (cmd->u.sedf.period < PERIOD_MIN) ||
         (cmd->u.sedf.slice  > cmd->u.sedf.period) ||
         (cmd->u.sedf.slice  < SLICE_MIN) )
        return -EINVAL;

period has bounds, slice cannot be greater than period, and slice cannot
be smaller than SLICE_MIN.  For any of these cases, the command will not
succeed.  You also might be interested in looking at
tools/xm-test/tests/sedf which has some simple sedf scheduler tests.

> 3. I tried to modify/readjust the slice/period length (or weights) for
> domains from command prompt.  However, I  found out that  changes are
> immaterial after first attempt. That is, no matter what changes I made at
> second or third or fourth time, they are not actually taking place. Only,
> the changes made during the first attempt actually took place. Please let me
> know if this is a bug in the existing code or I should have done the things
> in a different manner.

Could you supply the xm sched-sedf commands and values you used?

Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253

Xen-devel mailing list

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