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authorGerhard Engleder <gerhard@engleder-embedded.com>2022-05-06 22:01:41 +0200
committerPaolo Abeni <pabeni@redhat.com>2022-05-10 09:48:09 +0200
commitfcf308e50928a9c9eca90c56f9fc6885005dafd1 (patch)
tree951ac90c002ecfca1fe24c103724808712cdaec0 /drivers/ptp
parent97dc7cd92ac67f6e05df418df1772ba4a7fbf693 (diff)
ptp: Speed up vclock lookup
ptp_convert_timestamp() is called in the RX path of network messages. The current implementation takes ~5000ns on 1.2GHz A53. This is too much for the hot path of packet processing. Introduce hash table for fast vclock lookup in ptp_convert_timestamp(). The execution time of ptp_convert_timestamp() is reduced to ~700ns on 1.2GHz A53. Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'drivers/ptp')
-rw-r--r--drivers/ptp/ptp_private.h1
-rw-r--r--drivers/ptp/ptp_vclock.c66
2 files changed, 48 insertions, 19 deletions
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index ab47c10b3874..77918a2c6701 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -63,6 +63,7 @@ struct ptp_vclock {
struct ptp_clock *pclock;
struct ptp_clock_info info;
struct ptp_clock *clock;
+ struct hlist_node vclock_hash_node;
struct cyclecounter cc;
struct timecounter tc;
spinlock_t lock; /* protects tc/cc */
diff --git a/drivers/ptp/ptp_vclock.c b/drivers/ptp/ptp_vclock.c
index c30bcce2bb43..1c0ed4805c0a 100644
--- a/drivers/ptp/ptp_vclock.c
+++ b/drivers/ptp/ptp_vclock.c
@@ -5,6 +5,7 @@
* Copyright 2021 NXP
*/
#include <linux/slab.h>
+#include <linux/hashtable.h>
#include "ptp_private.h"
#define PTP_VCLOCK_CC_SHIFT 31
@@ -13,6 +14,32 @@
#define PTP_VCLOCK_FADJ_DENOMINATOR 15625ULL
#define PTP_VCLOCK_REFRESH_INTERVAL (HZ * 2)
+/* protects vclock_hash addition/deletion */
+static DEFINE_SPINLOCK(vclock_hash_lock);
+
+static DEFINE_READ_MOSTLY_HASHTABLE(vclock_hash, 8);
+
+static void ptp_vclock_hash_add(struct ptp_vclock *vclock)
+{
+ spin_lock(&vclock_hash_lock);
+
+ hlist_add_head_rcu(&vclock->vclock_hash_node,
+ &vclock_hash[vclock->clock->index % HASH_SIZE(vclock_hash)]);
+
+ spin_unlock(&vclock_hash_lock);
+}
+
+static void ptp_vclock_hash_del(struct ptp_vclock *vclock)
+{
+ spin_lock(&vclock_hash_lock);
+
+ hlist_del_init_rcu(&vclock->vclock_hash_node);
+
+ spin_unlock(&vclock_hash_lock);
+
+ synchronize_rcu();
+}
+
static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
struct ptp_vclock *vclock = info_to_vclock(ptp);
@@ -176,6 +203,8 @@ struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
snprintf(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",
pclock->index);
+ INIT_HLIST_NODE(&vclock->vclock_hash_node);
+
spin_lock_init(&vclock->lock);
vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);
@@ -187,11 +216,15 @@ struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
timecounter_init(&vclock->tc, &vclock->cc, 0);
ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);
+ ptp_vclock_hash_add(vclock);
+
return vclock;
}
void ptp_vclock_unregister(struct ptp_vclock *vclock)
{
+ ptp_vclock_hash_del(vclock);
+
ptp_clock_unregister(vclock->clock);
kfree(vclock);
}
@@ -234,34 +267,29 @@ EXPORT_SYMBOL(ptp_get_vclocks_index);
ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index)
{
- char name[PTP_CLOCK_NAME_LEN] = "";
+ unsigned int hash = vclock_index % HASH_SIZE(vclock_hash);
struct ptp_vclock *vclock;
- struct ptp_clock *ptp;
unsigned long flags;
- struct device *dev;
u64 ns;
+ u64 vclock_ns = 0;
- snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", vclock_index);
- dev = class_find_device_by_name(ptp_class, name);
- if (!dev)
- return 0;
+ ns = ktime_to_ns(*hwtstamp);
- ptp = dev_get_drvdata(dev);
- if (!ptp->is_virtual_clock) {
- put_device(dev);
- return 0;
- }
+ rcu_read_lock();
- vclock = info_to_vclock(ptp->info);
+ hlist_for_each_entry_rcu(vclock, &vclock_hash[hash], vclock_hash_node) {
+ if (vclock->clock->index != vclock_index)
+ continue;
- ns = ktime_to_ns(*hwtstamp);
+ spin_lock_irqsave(&vclock->lock, flags);
+ vclock_ns = timecounter_cyc2time(&vclock->tc, ns);
+ spin_unlock_irqrestore(&vclock->lock, flags);
+ break;
+ }
- spin_lock_irqsave(&vclock->lock, flags);
- ns = timecounter_cyc2time(&vclock->tc, ns);
- spin_unlock_irqrestore(&vclock->lock, flags);
+ rcu_read_unlock();
- put_device(dev);
- return ns_to_ktime(ns);
+ return ns_to_ktime(vclock_ns);
}
EXPORT_SYMBOL(ptp_convert_timestamp);
#endif