On Thu, Aug 30, 2012 at 01:38:42PM -0700, Paul E. McKenney wrote: > On Thu, Aug 30, 2012 at 12:00:18PM -0700, Josh Triplett wrote: > > On Thu, Aug 30, 2012 at 11:45:09AM -0700, Paul E. McKenney wrote: > > > From: "Paul E. McKenney" <[email protected]> > > > > > > Many rcutorture runs include CPU-hotplug operations in their stress > > > testing. This commit accumulates statistics on the durations of these > > > operations in deference to the recent concern about the overhead and > > > latency of these operations. > > > > How many jiffies, on average, do these operations take? Measuring these > > using jiffies seems highly prone to repeated rounding error. > > On my laptop, 30-140 depending on what hotplug patches I have in place. > Some users have reported as few as 2-3 jiffies, but they don't use > rcutorture. > > I eagerly look forward to the time when I need to change the timebase for > my own use. ;-)
Fair enough. In that case, this seems precise enough for the purpose it serves. > > > Signed-off-by: Paul E. McKenney <[email protected]> > > > Signed-off-by: Paul E. McKenney <[email protected]> Reviewed-by: Josh Triplett <[email protected]> > > > --- > > > kernel/rcutorture.c | 42 +++++++++++++++++++++++++++++++++++++----- > > > 1 files changed, 37 insertions(+), 5 deletions(-) > > > > > > diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c > > > index 86315d3..c6cf6ff 100644 > > > --- a/kernel/rcutorture.c > > > +++ b/kernel/rcutorture.c > > > @@ -176,8 +176,14 @@ static long n_rcu_torture_boosts; > > > static long n_rcu_torture_timers; > > > static long n_offline_attempts; > > > static long n_offline_successes; > > > +static unsigned long sum_offline; > > > +static int min_offline = -1; > > > +static int max_offline; > > > static long n_online_attempts; > > > static long n_online_successes; > > > +static unsigned long sum_online; > > > +static int min_online = -1; > > > +static int max_online; > > > static long n_barrier_attempts; > > > static long n_barrier_successes; > > > static struct list_head rcu_torture_removed; > > > @@ -1214,11 +1220,13 @@ rcu_torture_printk(char *page) > > > n_rcu_torture_boost_failure, > > > n_rcu_torture_boosts, > > > n_rcu_torture_timers); > > > - cnt += sprintf(&page[cnt], "onoff: %ld/%ld:%ld/%ld ", > > > - n_online_successes, > > > - n_online_attempts, > > > - n_offline_successes, > > > - n_offline_attempts); > > > + cnt += sprintf(&page[cnt], > > > + "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", > > > + n_online_successes, n_online_attempts, > > > + n_offline_successes, n_offline_attempts, > > > + min_online, max_online, > > > + min_offline, max_offline, > > > + sum_online, sum_offline, HZ); > > > cnt += sprintf(&page[cnt], "barrier: %ld/%ld:%ld", > > > n_barrier_successes, > > > n_barrier_attempts, > > > @@ -1490,8 +1498,10 @@ static int __cpuinit > > > rcu_torture_onoff(void *arg) > > > { > > > int cpu; > > > + unsigned long delta; > > > int maxcpu = -1; > > > DEFINE_RCU_RANDOM(rand); > > > + unsigned long starttime; > > > > > > VERBOSE_PRINTK_STRING("rcu_torture_onoff task started"); > > > for_each_online_cpu(cpu) > > > @@ -1509,6 +1519,7 @@ rcu_torture_onoff(void *arg) > > > printk(KERN_ALERT "%s" TORTURE_FLAG > > > "rcu_torture_onoff task: offlining %d\n", > > > torture_type, cpu); > > > + starttime = jiffies; > > > n_offline_attempts++; > > > if (cpu_down(cpu) == 0) { > > > if (verbose) > > > @@ -1516,12 +1527,23 @@ rcu_torture_onoff(void *arg) > > > "rcu_torture_onoff task: > > > offlined %d\n", > > > torture_type, cpu); > > > n_offline_successes++; > > > + delta = jiffies - starttime; > > > + sum_offline += delta; > > > + if (min_offline < 0) { > > > + min_offline = delta; > > > + max_offline = delta; > > > + } > > > + if (min_offline > delta) > > > + min_offline = delta; > > > + if (max_offline < delta) > > > + max_offline = delta; > > > } > > > } else if (cpu_is_hotpluggable(cpu)) { > > > if (verbose) > > > printk(KERN_ALERT "%s" TORTURE_FLAG > > > "rcu_torture_onoff task: onlining %d\n", > > > torture_type, cpu); > > > + starttime = jiffies; > > > n_online_attempts++; > > > if (cpu_up(cpu) == 0) { > > > if (verbose) > > > @@ -1529,6 +1551,16 @@ rcu_torture_onoff(void *arg) > > > "rcu_torture_onoff task: onlined > > > %d\n", > > > torture_type, cpu); > > > n_online_successes++; > > > + delta = jiffies - starttime; > > > + sum_online += delta; > > > + if (min_online < 0) { > > > + min_online = delta; > > > + max_online = delta; > > > + } > > > + if (min_online > delta) > > > + min_online = delta; > > > + if (max_online < delta) > > > + max_online = delta; > > > } > > > } > > > schedule_timeout_interruptible(onoff_interval * HZ); > > > -- > > > 1.7.8 > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
