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McKenney" 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, patches@linaro.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 02/14] rcu: Trace callback acceleration Date: Sat, 5 Jan 2013 09:48:52 -0800 Message-Id: <1357408144-15830-2-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1357408144-15830-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20130105174844.GA14172@linux.vnet.ibm.com> <1357408144-15830-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13010517-7282-0000-0000-000012CCA91A X-Gm-Message-State: ALoCoQmZjHw8lf0ybGA6Ys07gWknnr0bCko3COZLiWjaPGTbbQ4h2femimqFa4Vi6ey2HbgSJehQ From: "Paul E. McKenney" This commit adds event tracing for callback acceleration to allow better tracking of callbacks through the system. Signed-off-by: Paul E. McKenney --- 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"); } /*