From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hannes Reinecke <hare@suse.de>
Subject: Re: [multipath tools] pgp->priority average calculation
Date: Wed, 09 Jan 2013 08:35:44 +0100
Message-ID: <50ED1DD0.9090900@suse.de>
References: <50ECA2F3.7070501@cs.wisc.edu>
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To: Mike Christie <michaelc@cs.wisc.edu>
Cc: device-mapper development <dm-devel@redhat.com>, christophe.varoqui@gmail.com
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On 01/08/2013 11:51 PM, Mike Christie wrote:
> Hey Ben and Hannes and Christophe,
>
> Happy multipath-tools patch submission day :)
>
> I had a question on the pgp->priority average calculation and its
> display to the user.
>
>
> Ben, you added the patch
>
> commit cd21bd290a57eed350d564bac403da9d6941a144
> Author: Benjamin Marzinski <bmarzins@redhat.com>
> Date:   Wed Nov 10 12:52:20 2010 -0600
>
>      multipath: sort all pathgroups by priority
>
>
> which did
>
> @@ -25,14 +25,17 @@ path_group_prio_update (struct pathgroup * pgp)
>                          pgp->enabled_paths++;
>                  }
>          }
> -       pgp->priority =3D priority;
> +       if (pgp->enabled_paths)
> +               pgp->priority =3D priority / pgp->enabled_paths;
> +       else
> +
>
> and
>
> @@ -387,9 +386,7 @@ snprint_pg_pri (char * buff, size_t len, struct
> pathgroup *
>           * Printing is another reason to update.
>           */
>          path_group_prio_update(pgp);
> -       if (pgp->enabled_paths)
> -               avg_priority =3D pgp->priority / pgp->enabled_paths;
> -       return snprint_int(buff, len, avg_priority);
> +
>
>
> but then Hannes later added the patch:
>
>
> commit 750db1f0dc08bf1d96ce64d32786dfe07b8ae3f9
> Author: Hannes Reinecke <hare@suse.de>
> Date:   Wed Mar 17 08:32:51 2010 +0100
>
>      Display avg priority as group priority
>
>
> which added it back in the print code:
>
>
> -       return snprint_int(buff, len, pgp->priority);
> +       if (pgp->enabled_paths)
> +               avg_priority =3D pgp->priority / pgp->enabled_paths;
> +       return snprint_int(buff, len, avg_priority);
>
>
> So when we print the prio, it ends up getting divided by the number of
> enabled paths twice.
>
>
> Was Hannes's patch a mistake? Should it be reverted?
>
Yeah, that seems to be an error.
Please revert.

Cheers,

Hannes
-- =

Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg
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