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author | Paul E. McKenney <paul.mckenney@linaro.org> | 2011-11-22 22:58:03 (GMT) |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-12-11 18:32:00 (GMT) |
commit | 433cdddcd9ac5558068edd7f8d4707a70f7710f5 (patch) | |
tree | 7f3686eb64c9ee3a239e5920df588c70837c5637 /include/trace/events | |
parent | 045fb9315a2129023d70a0eecf0942e18fca4fcd (diff) | |
download | linux-fsl-qoriq-433cdddcd9ac5558068edd7f8d4707a70f7710f5.tar.xz |
rcu: Add tracing for RCU_FAST_NO_HZ
This commit adds trace_rcu_prep_idle(), which is invoked from
rcu_prepare_for_idle() and rcu_wake_cpu() to trace attempts on
the part of RCU to force CPUs into dyntick-idle mode.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/trace/events')
-rw-r--r-- | include/trace/events/rcu.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 7f6877a..debe453 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -275,6 +275,42 @@ TRACE_EVENT(rcu_dyntick, ); /* + * Tracepoint for RCU preparation for idle, the goal being to get RCU + * processing done so that the current CPU can shut off its scheduling + * clock and enter dyntick-idle mode. One way to accomplish this is + * to drain all RCU callbacks from this CPU, and the other is to have + * done everything RCU requires for the current grace period. In this + * latter case, the CPU will be awakened at the end of the current grace + * period in order to process the remainder of its callbacks. + * + * These tracepoints take a string as argument: + * + * "No callbacks": Nothing to do, no callbacks on this CPU. + * "In holdoff": Nothing to do, holding off after unsuccessful attempt. + * "Dyntick with callbacks": Callbacks remain, but RCU doesn't need CPU. + * "Begin holdoff": Attempt failed, don't retry until next jiffy. + * "More callbacks": Still more callbacks, try again to clear them out. + * "Callbacks drained": All callbacks processed, off to dyntick idle! + * "CPU awakened at GP end": + */ +TRACE_EVENT(rcu_prep_idle, + + TP_PROTO(char *reason), + + TP_ARGS(reason), + + TP_STRUCT__entry( + __field(char *, reason) + ), + + TP_fast_assign( + __entry->reason = reason; + ), + + TP_printk("%s", __entry->reason) +); + +/* * Tracepoint for the registration of a single RCU callback function. * The first argument is the type of RCU, the second argument is * a pointer to the RCU callback itself, and the third element is the @@ -482,6 +518,7 @@ TRACE_EVENT(rcu_torture_read, #define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, grplo, grphi, gp_tasks) do { } while (0) #define trace_rcu_fqs(rcuname, gpnum, cpu, qsevent) do { } while (0) #define trace_rcu_dyntick(polarity, oldnesting, newnesting) do { } while (0) +#define trace_rcu_prep_idle(reason) do { } while (0) #define trace_rcu_callback(rcuname, rhp, qlen) do { } while (0) #define trace_rcu_kfree_callback(rcuname, rhp, offset, qlen) do { } while (0) #define trace_rcu_batch_start(rcuname, qlen, blimit) do { } while (0) |