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author | Paul E. McKenney <paulmck@kernel.org> | 2023-07-12 04:01:38 +0300 |
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committer | Paul E. McKenney <paulmck@kernel.org> | 2023-07-15 01:01:04 +0300 |
commit | b5a2801fc05350b3b81e6fdcefddd6cfdbf8b238 (patch) | |
tree | d68113f1971aff396bf9875c4be5757ed2519a33 /kernel/rcu/refscale.c | |
parent | f5063e8948dad7f31adb007284a5d5038ae31bb8 (diff) | |
download | linux-b5a2801fc05350b3b81e6fdcefddd6cfdbf8b238.tar.xz |
refscale: Add a "jiffies" test
This commit adds a "jiffies" test to refscale, allowing use of jiffies
to be compared to ktime_get_real_fast_ns(). On my x86 laptop, jiffies
is more than 20x faster. (Though for many uses, the tens-of-nanoseconds
overhead of ktime_get_real_fast_ns() will be just fine.)
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/refscale.c')
-rw-r--r-- | kernel/rcu/refscale.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 71d138573856..91a0fd0d4d9a 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -528,6 +528,38 @@ static struct ref_scale_ops clock_ops = { .name = "clock" }; +static void ref_jiffies_section(const int nloops) +{ + u64 x = 0; + int i; + + preempt_disable(); + for (i = nloops; i >= 0; i--) + x += jiffies; + preempt_enable(); + stopopts = x; +} + +static void ref_jiffies_delay_section(const int nloops, const int udl, const int ndl) +{ + u64 x = 0; + int i; + + preempt_disable(); + for (i = nloops; i >= 0; i--) { + x += jiffies; + un_delay(udl, ndl); + } + preempt_enable(); + stopopts = x; +} + +static struct ref_scale_ops jiffies_ops = { + .readsection = ref_jiffies_section, + .delaysection = ref_jiffies_delay_section, + .name = "jiffies" +}; + //////////////////////////////////////////////////////////////////////// // // Methods leveraging SLAB_TYPESAFE_BY_RCU. @@ -1047,7 +1079,7 @@ ref_scale_init(void) int firsterr = 0; static struct ref_scale_ops *scale_ops[] = { &rcu_ops, &srcu_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &rwlock_ops, - &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops, + &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops, &jiffies_ops, &typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops, }; |