From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 12 Nov 2012 02:40:23 +0000 (-0500)
Subject: urcu-qsbr: improve 2-phase wait scheme
X-Git-Tag: v0.8.0~146
X-Git-Url: https://git.liburcu.org/?a=commitdiff_plain;h=f6b42f9c22f265a7c071a8b60c546a76faa5f69b;hp=f6b42f9c22f265a7c071a8b60c546a76faa5f69b;p=urcu.git

urcu-qsbr: improve 2-phase wait scheme

In the single-bit, 2-phase grace period scheme, all we need to do is to
observe each reader going through a quiescent state while we are in the
grace period.

We therefore only need to perform one global counter update, surrounded
by 2 iterations on readers to observe change in their snapshot.

We can therefore remove the first counter update (prior to the first
iteration on readers): it was useless and was only slowing down the
grace period.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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