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[Xen-devel] [PATCH] Reduce overhead in find_domain_by_id() [0/2]

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Subject: [Xen-devel] [PATCH] Reduce overhead in find_domain_by_id() [0/2]
From: "Santos, Jose Renato G" <joserenato.santos@xxxxxx>
Date: Tue, 5 Dec 2006 19:35:37 -0600
Cc: Yoshio Turner <yoshiotu@xxxxxxxxxx>, Jose Renato Santos <jsantos@xxxxxxxxxx>, G John Janakiraman <john@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 05 Dec 2006 17:35:41 -0800
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Thread-index: AccY1tScspQxhfmoTr62Wf8QIRwz8w==
Thread-topic: [PATCH] Reduce overhead in find_domain_by_id() [0/2]
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.

Renato

Patches:
  1/2 - Import linux RCU code into Xen
  2/2 - replace domlist_lock operations by RCU operations

Signed-off-by: Jose Renato Santos <jsantos@xxxxxxxxxx>

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