Commit e7fd2885 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

net-timestamp: SCHED timestamp on entering packet scheduler 



Kernel transmit latency is often incurred in the packet scheduler.
Introduce a new timestamp on transmission just before entering the
scheduler. When data travels through multiple devices (bonding,
tunneling, ...) each device will export an individual timestamp.

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 09c2d251

include/linux/skbuff.h

+9 −2
Original line number Diff line number Diff line
@@ -229,7 +229,7 @@ enum { 
	/* generate hardware time stamp */

	SKBTX_HW_TSTAMP = 1 << 0,



	/* generate software time stamp */

	/* generate software time stamp when queueing packet to NIC */

	SKBTX_SW_TSTAMP = 1 << 1,



	/* device driver is going to provide hardware time stamp */
@@ -247,9 +247,12 @@ enum { 
	 * all frags to avoid possible bad checksum

	 */

	SKBTX_SHARED_FRAG = 1 << 5,



	/* generate software time stamp when entering packet scheduling */

	SKBTX_SCHED_TSTAMP = 1 << 6,

};



#define SKBTX_ANY_SW_TSTAMP	SKBTX_SW_TSTAMP

#define SKBTX_ANY_SW_TSTAMP	(SKBTX_SW_TSTAMP | SKBTX_SCHED_TSTAMP)

#define SKBTX_ANY_TSTAMP	(SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)



/*
@@ -2695,6 +2698,10 @@ static inline bool skb_defer_rx_timestamp(struct sk_buff *skb) 
void skb_complete_tx_timestamp(struct sk_buff *skb,

			       struct skb_shared_hwtstamps *hwtstamps);



void __skb_tstamp_tx(struct sk_buff *orig_skb,

		     struct skb_shared_hwtstamps *hwtstamps,

		     struct sock *sk, int tstype);



/**

 * skb_tstamp_tx - queue clone of skb with send time stamps

 * @orig_skb:	the original outgoing packet

include/uapi/linux/errqueue.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ struct scm_timestamping { 
 */

enum {

	SCM_TSTAMP_SND,		/* driver passed skb to NIC, or HW */

	SCM_TSTAMP_SCHED,	/* data entered the packet scheduler */

};



#endif /* _UAPI_LINUX_ERRQUEUE_H */

include/uapi/linux/net_tstamp.h

+2 −1
Original line number Diff line number Diff line
@@ -21,8 +21,9 @@ enum { 
	SOF_TIMESTAMPING_SYS_HARDWARE = (1<<5),

	SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6),

	SOF_TIMESTAMPING_OPT_ID = (1<<7),

	SOF_TIMESTAMPING_TX_SCHED = (1<<8),



	SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID,

	SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_SCHED,

	SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |

				 SOF_TIMESTAMPING_LAST

};

net/core/dev.c

+4 −0
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ 
#include <linux/hashtable.h>

#include <linux/vmalloc.h>

#include <linux/if_macvlan.h>

#include <linux/errqueue.h>



#include "net-sysfs.h"
@@ -2876,6 +2877,9 @@ static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv) 


	skb_reset_mac_header(skb);



	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP))

		__skb_tstamp_tx(skb, NULL, skb->sk, SCM_TSTAMP_SCHED);



	/* Disable soft irqs for various locks below. Also

	 * stops preemption for RCU.

	 */

net/core/skbuff.c

+12 −4
Original line number Diff line number Diff line
@@ -3490,10 +3490,10 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) 
}

EXPORT_SYMBOL(sock_queue_err_skb);



void skb_tstamp_tx(struct sk_buff *orig_skb,

		struct skb_shared_hwtstamps *hwtstamps)

void __skb_tstamp_tx(struct sk_buff *orig_skb,

		     struct skb_shared_hwtstamps *hwtstamps,

		     struct sock *sk, int tstype)

{

	struct sock *sk = orig_skb->sk;

	struct sock_exterr_skb *serr;

	struct sk_buff *skb;

	int err;
@@ -3521,7 +3521,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
	memset(serr, 0, sizeof(*serr));

	serr->ee.ee_errno = ENOMSG;

	serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;

	serr->ee.ee_info = SCM_TSTAMP_SND;

	serr->ee.ee_info = tstype;

	if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)

		serr->ee.ee_data = skb_shinfo(skb)->tskey;
@@ -3530,6 +3530,14 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
	if (err)

		kfree_skb(skb);

}

EXPORT_SYMBOL_GPL(__skb_tstamp_tx);



void skb_tstamp_tx(struct sk_buff *orig_skb,

		   struct skb_shared_hwtstamps *hwtstamps)

{

	return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,

			       SCM_TSTAMP_SND);

}

EXPORT_SYMBOL_GPL(skb_tstamp_tx);



void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)

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