From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: [PATCH] Reduce overhead in find_domain_by_id() [0/2]
Date: Wed, 06 Dec 2006 08:43:32 +0000
Message-ID: <C19C3334.56DF%keir@xensource.com>
References: <08CA2245AFCF444DB3AC415E47CC40AF50830E@G3W0072.americas.hpqcorp.net>
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To: "Santos, Jose Renato G" <joserenato.santos@hp.com>, xen-devel@lists.xensource.com
Cc: Yoshio Turner <yoshiotu@hpl.hp.com>, Jose Renato Santos <jsantos@hpl.hp.com>, G John Janakiraman <john@arivalai.hpl.hp.com>
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On 6/12/06 1:35 am, "Santos, Jose Renato G" <joserenato.santos@hp.com>
wrote:

> 
> This is a set of patches to improve performance of find_domain_by_id().
> find_domain_by_id shows up high in profiles for network I/O intensive
> workloads.
> Most of the cost for this function comes from 3 main functions (of
> aproximate equal costs): 1)read_lock(), 2)read_unlock() and
> 3)get_domain().
> These patches replace the lock used for accessing domain_list and
> domain_hash with a lock free RCU scheme. Experiments confirm that the
> cost of find_domain_by_id() is in fact reduced by 2/3.
> The patches apply cleanly to changeset 12732.

Do you have numbers for performance improvement on a macro benchmark?

 -- Keir