kernel_optimize_test/include/net/pkt_sched.h
Eric Dumazet 45f50bed1d net_sched: remove generic throttled management
__QDISC_STATE_THROTTLED bit manipulation is rather expensive
for HTB and few others.

I already removed it for sch_fq in commit f2600cf02b
("net: sched: avoid costly atomic operation in fq_dequeue()")
and so far nobody complained.

When one ore more packets are stuck in one or more throttled
HTB class, a htb dequeue() performs two atomic operations
to clear/set __QDISC_STATE_THROTTLED bit, while root qdisc
lock is held.

Removing this pair of atomic operations bring me a 8 % performance
increase on 200 TCP_RR tests, in presence of throttled classes.

This patch has no side effect, since nothing actually uses
disc_is_throttled() anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-10 23:58:21 -07:00

137 lines
3.8 KiB
C

#ifndef __NET_PKT_SCHED_H
#define __NET_PKT_SCHED_H
#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/if_vlan.h>
#include <net/sch_generic.h>
struct qdisc_walker {
int stop;
int skip;
int count;
int (*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
};
#define QDISC_ALIGNTO 64
#define QDISC_ALIGN(len) (((len) + QDISC_ALIGNTO-1) & ~(QDISC_ALIGNTO-1))
static inline void *qdisc_priv(struct Qdisc *q)
{
return (char *) q + QDISC_ALIGN(sizeof(struct Qdisc));
}
/*
Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
Normal IP packet size ~ 512byte, hence:
0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
10Mbit ethernet.
10msec resolution -> <50Kbit/sec.
The result: [34]86 is not good choice for QoS router :-(
The things are not so bad, because we may use artificial
clock evaluated by integration of network data flow
in the most critical places.
*/
typedef u64 psched_time_t;
typedef long psched_tdiff_t;
/* Avoid doing 64 bit divide */
#define PSCHED_SHIFT 6
#define PSCHED_TICKS2NS(x) ((s64)(x) << PSCHED_SHIFT)
#define PSCHED_NS2TICKS(x) ((x) >> PSCHED_SHIFT)
#define PSCHED_TICKS_PER_SEC PSCHED_NS2TICKS(NSEC_PER_SEC)
#define PSCHED_PASTPERFECT 0
static inline psched_time_t psched_get_time(void)
{
return PSCHED_NS2TICKS(ktime_get_ns());
}
static inline psched_tdiff_t
psched_tdiff_bounded(psched_time_t tv1, psched_time_t tv2, psched_time_t bound)
{
return min(tv1 - tv2, bound);
}
struct qdisc_watchdog {
u64 last_expires;
struct hrtimer timer;
struct Qdisc *qdisc;
};
void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires);
static inline void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
psched_time_t expires)
{
qdisc_watchdog_schedule_ns(wd, PSCHED_TICKS2NS(expires));
}
void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);
extern struct Qdisc_ops pfifo_qdisc_ops;
extern struct Qdisc_ops bfifo_qdisc_ops;
extern struct Qdisc_ops pfifo_head_drop_qdisc_ops;
int fifo_set_limit(struct Qdisc *q, unsigned int limit);
struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
unsigned int limit);
int register_qdisc(struct Qdisc_ops *qops);
int unregister_qdisc(struct Qdisc_ops *qops);
void qdisc_get_default(char *id, size_t len);
int qdisc_set_default(const char *id);
void qdisc_list_add(struct Qdisc *q);
void qdisc_list_del(struct Qdisc *q);
struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
struct nlattr *tab);
void qdisc_put_rtab(struct qdisc_rate_table *tab);
void qdisc_put_stab(struct qdisc_size_table *tab);
void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc);
int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
struct net_device *dev, struct netdev_queue *txq,
spinlock_t *root_lock, bool validate);
void __qdisc_run(struct Qdisc *q);
static inline void qdisc_run(struct Qdisc *q)
{
if (qdisc_run_begin(q))
__qdisc_run(q);
}
int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res, bool compat_mode);
static inline __be16 tc_skb_protocol(const struct sk_buff *skb)
{
/* We need to take extra care in case the skb came via
* vlan accelerated path. In that case, use skb->vlan_proto
* as the original vlan header was already stripped.
*/
if (skb_vlan_tag_present(skb))
return skb->vlan_proto;
return skb->protocol;
}
/* Calculate maximal size of packet seen by hard_start_xmit
routine of this device.
*/
static inline unsigned int psched_mtu(const struct net_device *dev)
{
return dev->mtu + dev->hard_header_len;
}
#endif