diff options
author | Gerhard Engleder <gerhard@engleder-embedded.com> | 2022-05-06 22:01:41 +0200 |
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committer | Paolo Abeni <pabeni@redhat.com> | 2022-05-10 09:48:09 +0200 |
commit | fcf308e50928a9c9eca90c56f9fc6885005dafd1 (patch) | |
tree | 951ac90c002ecfca1fe24c103724808712cdaec0 /drivers/ptp | |
parent | 97dc7cd92ac67f6e05df418df1772ba4a7fbf693 (diff) | |
download | linux-stable-fcf308e50928a9c9eca90c56f9fc6885005dafd1.tar.gz linux-stable-fcf308e50928a9c9eca90c56f9fc6885005dafd1.tar.bz2 linux-stable-fcf308e50928a9c9eca90c56f9fc6885005dafd1.zip |
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.h | 1 | ||||
-rw-r--r-- | drivers/ptp/ptp_vclock.c | 66 |
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 |