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authorPaul E. McKenney <paulmck@linux.ibm.com>2018-10-06 02:43:09 +0300
committerPaul E. McKenney <paulmck@linux.ibm.com>2018-12-01 23:45:41 +0300
commit2e57bf97a6856f2dc10fb4377c452cb08f844047 (patch)
tree3617b1482c7d9400708645b2729e87c65f995fa5 /kernel/rcu/rcutorture.c
parent2667ccce9328e4e25ed77a83291c066d5e11e65a (diff)
downloadlinux-2e57bf97a6856f2dc10fb4377c452cb08f844047.tar.xz
rcutorture: Use 100ms buckets for forward-progress callback histograms
This commit narrows the scope of each bucket of the forward-progress callback-invocation histograms from one second to 100 milliseconds, which aids debugging of forward-progress problems by making shorter-duration callback-invocation stalls visible. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu/rcutorture.c')
-rw-r--r--kernel/rcu/rcutorture.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index afa98162575d..a4c4a24bdcaa 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1629,7 +1629,8 @@ static bool rcu_fwd_emergency_stop;
#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
-static long n_launders_hist[2 * MAX_FWD_CB_JIFFIES / HZ];
+#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
+static long n_launders_hist[2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)];
static void rcu_torture_fwd_cb_hist(void)
{
@@ -1642,7 +1643,8 @@ static void rcu_torture_fwd_cb_hist(void)
pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
__func__, jiffies - rcu_fwd_startat);
for (j = 0; j <= i; j++)
- pr_cont(" %ds: %ld", j + 1, n_launders_hist[j]);
+ pr_cont(" %ds/%d: %ld",
+ j + 1, FWD_CBS_HIST_DIV, n_launders_hist[j]);
pr_cont("\n");
}
@@ -1661,7 +1663,7 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
rcu_fwd_cb_tail = &rfcp->rfc_next;
WRITE_ONCE(*rfcpp, rfcp);
WRITE_ONCE(n_launders_cb, n_launders_cb + 1);
- i = ((jiffies - rcu_fwd_startat) / HZ);
+ i = ((jiffies - rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
if (i >= ARRAY_SIZE(n_launders_hist))
i = ARRAY_SIZE(n_launders_hist) - 1;
n_launders_hist[i]++;