From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 2/2] rcu: Trace callback acceleration
Date: Sat, 26 Jan 2013 16:18:21 -0800 [thread overview]
Message-ID: <1359245901-4432-2-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1359245901-4432-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
This commit adds event tracing for callback acceleration to allow better
tracking of callbacks through the system.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/trace/events/rcu.h | 6 ++++--
kernel/rcutree.c | 6 ++++++
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index d4f559b..5678114 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -44,8 +44,10 @@ TRACE_EVENT(rcu_utilization,
* of a new grace period or the end of an old grace period ("cpustart"
* and "cpuend", respectively), a CPU passing through a quiescent
* state ("cpuqs"), a CPU coming online or going offline ("cpuonl"
- * and "cpuofl", respectively), and a CPU being kicked for being too
- * long in dyntick-idle mode ("kick").
+ * and "cpuofl", respectively), a CPU being kicked for being too
+ * long in dyntick-idle mode ("kick"), a CPU accelerating its new
+ * callbacks to RCU_NEXT_READY_TAIL ("AccReadyCB"), and a CPU
+ * accelerating its new callbacks to RCU_WAIT_TAIL ("AccWaitCB").
*/
TRACE_EVENT(rcu_grace_period,
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index ac6a75d..e9dce4f 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1168,6 +1168,12 @@ static void rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
rdp->nxttail[i] = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxtcompleted[i] = c;
}
+
+ /* Trace depending on how much we were able to accelerate. */
+ if (!*rdp->nxttail[RCU_WAIT_TAIL])
+ trace_rcu_grace_period(rsp->name, rdp->gpnum, "AccWaitCB");
+ else
+ trace_rcu_grace_period(rsp->name, rdp->gpnum, "AccReadyCB");
}
/*
--
1.7.8
next prev parent reply other threads:[~2013-01-27 5:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-27 0:18 [PATCH tip/core/rcu 0/2] Callback tagging for 3.9 Paul E. McKenney
2013-01-27 0:18 ` [PATCH tip/core/rcu 1/2] rcu: Tag callback lists with corresponding grace-period number Paul E. McKenney
2013-01-27 0:18 ` Paul E. McKenney [this message]
2013-01-27 10:51 ` [PATCH tip/core/rcu 2/2] rcu: Trace callback acceleration Josh Triplett
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