From: Joe Korty <joe.korty@ccur.com>
To: paulmck@linux.vnet.ibm.com
Cc: fweisbec@gmail.com, peterz@infradead.org, laijs@cn.fujitsu.com,
mathieu.desnoyers@efficios.com, dhowells@redhat.com,
loic.minier@linaro.org, dhaval.giani@gmail.com,
tglx@linutronix.de, josh@joshtriplett.org,
houston.jim@comcast.net, andi@firstfloor.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 23/24] jrcu: better timer slop
Date: Thu, 24 Mar 2011 13:48:04 -0400 [thread overview]
Message-ID: <20110324174804.GA18965@tsunami.ccur.com> (raw)
jrcu: fix broken timer slop
The expression
USEC_PER_SEC / (HZ * 3 / 2)
was trying to define a period, in usec, some 50% larger
than the natural HZ period. Instead it made a period
some 30% shorter.
But such attempts are completely unnecessary. HZ alone
works just fine.
Signed-off-by: Joe Korty <joe.korty@ccur.com>
Index: b/kernel/jrcu.c
===================================================================
--- a/kernel/jrcu.c
+++ b/kernel/jrcu.c
@@ -131,7 +131,7 @@ static struct rcu_stats {
#define RCU_HZ (20)
#define RCU_HZ_PERIOD_US (USEC_PER_SEC / RCU_HZ)
-#define RCU_HZ_DELTA_US (USEC_PER_SEC / (HZ * 3 / 2))
+#define RCU_HZ_DELTA_US (USEC_PER_SEC / HZ)
static int rcu_hz = RCU_HZ;
static int rcu_hz_period_us = RCU_HZ_PERIOD_US;
reply other threads:[~2011-03-24 17:50 UTC|newest]
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